Identifying the important roles that functional groups play when substituted alkynes are placed under hydroformylation conditions (reactions incorporating carbon monoxide and hydrogen gas with catalytic amounts of a rhodium complex) is a valuable tool for organic synthesis. Novel and unexpected chemistry have resulted from establishing the primary and secondary roles of certain functional groups. The primary role is the ability to direct a rhodium complex to add to a triple bond, and the secondary role involves directing the type of chemistry that will take place after the addition. The following examples demonstrate this dual relationship resulting in the preparation of alpha,beta-unsaturated aldehydes, N-heterocyclec enols, and important ring systems with potential biological activity. The selected 5-membered heterocycles generated are important materials in treating inflammatory diseases, cancer and heart disease, as well as allowing for the inhibition of HIV protease. The reaction of aliphatic 1-en-3-ynes with synthesis gas in the presence of the zwitterionic rhodium complex, (eta6-C6H 5BPh3)-Rh+(1,5-COD) and triphenyl phosphite afford formyl-dienes in high regioselectivity, and in 50 to 70% isolated yields. As well, the hydroformylation of 2-acetylenic thiophenes afford, as the major product, the alpha,beta-unsaturated aldehyde with the aldehyde and thiophene attached to the same olefin carbon atom. Excellent regioselectivities of 64 to 100% and additive yields of 65 to 97% were obtained when the acetylenic unit is a propargyl ether or ester, phenylacetylene, or an enyne. alpha-Keto alkynes react with CO/H2 in the presence of catalytic quantities of the zwitterionic rhodium complex and triphenyl phosphite to form either the 2-, 2(3H)- or 2(5H)-furanones in 61--93% yields. In addition, the tandem cyclohydrocarbonylative/CO insertion of alpha-imino alkynes afford aldehyde substituted pyrrolinones in 67 to 82% yields. Hydrocarbonylative enolation of 2-acetylenic thiazoles in the presence of CO, H2 and catalytic quantities of the zwitterionic rhodium complex and triphenyl phosphite afford (Z)-2-thiazol-2-ylalk-1en-1ols in 61 to 90% yields. The extension of the hydrocarbonylative enolation to 2-acetylenic benzoxazoles give (Z)-2-benzoxazol-2-ylalk-1-en-1-ols in 37 to 87% yields.

A series of rigid neoglycoclusters and dimers were synthesized from sugar alkynes using Sonogashira coupling. Rigid dimers consisting of two mannoside or galactoside derivatives tethered to a phenylacetylene core were constructed. By oxidative coupling of glycosidic terminal acetylenes, rigid dimers consisting of two mannoside residues tethered to a diphenyl-di-acetylene core were synthesized. Utilizing the ortho-, meta- and para-acetylene substituted phenyls, rigid dimers having monosaccharide units oriented at 60°, 120° and 180° with each other were generated. Convergent synthesis of glycosidic clusters emanating from a benzene core was attained utilizing Co2(CO)8 catalyzed cyclotrimerization of acetylenes disubstituted with monosaccharide residues. Trimers and hexamers, including a hexameric "molecular asterisk" were constructed. Galactoside and mannoside clusters were synthesized. Semi-rigid dimers were also synthesized by O-glycosidation of dihydroxybenzene and 2-butyn-1,4-diol. Preliminary binding studies of the mannoside dimers, trimer and hexamers revealed that the hexamer and rigid dimers having two phenyl-acetylenes at the core have promising activity vs. the phytohemagglutinin from Canavalia ensiformis (ConA.). Optimum binding with ConA was demonstrated by the para-disubstituted di-phenyl-diacetylene and the molecular asterisk. These two compounds showed comparable activities giving an indication of the minimum binding requirements of mannosaccharide conjugates with Concanavalin A.

Section I. The new disaccharide, crystalline (6-deoxy-$\alpha$-D-gluco-heptopyranosyluronic acid) 6-deoxy-$\alpha$-D-gluco-heptopyranosiduronic acid 5 was synthesized from $\alpha, \alpha$-trehalose 1. Reaction of 2,3,4,2$\sp\prime$,3$\sp\prime$,4$\sp\prime$-hexa-O-acetyl-6,6$\sp\prime$-di-O-tosyl-$\alpha, \alpha$-trehalose 7 with sodium dicarbonylcyclopentadienyliron, followed by oxidative carbonyl insertion and hydrolysis with bromine and water, gave the 2,3,4,2$\sp\prime$,3$\sp\prime$,4$\sp\prime$-hexa-acetate 16 of 5, which was then O-deacetylated (Zemplen). The protected bis-heptosiduronic acid, (2,3,4-tri-O-benzyl-6-deoxy-$\alpha$-D-gluco-heptopyranosyluronic acid) 2,3,4-tri-O-benzyl-6-deoxy-$\alpha$-D-gluco-heptopyranosiduronic acid 26, was similarly synthesized by the ironcarbonyl method of chain elongation, starting from 2,3,4,2$\sp\prime$,3$\sp\prime$,4$\sp \prime$-hexa-O-benzyl-6,6$\sp\prime$-di-O-tosyl-$\alpha, \alpha$-trehalose 24. In this case, oxidative carbonyl insertion was effected with iodine in the presence of methanol, and the dimethyl ester 25 obtained was subsequently saponified to 26. The dimethyl ester 25 was also prepared by acid-catalyzed methanolysis of the corresponding diamide 29, which can be obtained from the ditosylate 24 by cyanide displacement and alkaline hydrolysis of the resulting dinitrile 28. Mitsunobu esterification of the diacid 26 with (racemic) diastereomeric 3-O-benzylcorynomycolyl alcohols, obtained by reduction of synthetic, 3-O-benzylated methyl C$\sb{32}$-corynomycolates with lithium aluminum hydride, furnished the corresponding diesters in high yields. Hydrogenolytic debenzylation of the products led to "mirror" coryno-cord factors 47a and 47b. Section II. Approaches to chain extension at the C-6 positions in cyclomaltoheptaose (2) were examined with the aim of producing novel beta-cyclodextrin analogs composed of heptose or hepturonic acid units. Ironcarbonyl-mediated methoxycarbonylation, and nucleophilic displacement by cyanide, in the fully acetylated heptakis(6-deoxy-6-iodo) and heptakis(6-O-mesyl) derivatives of 2 respectively were unsuccessful, as were similar reactions attempted with the newly synthesized, analogous allyl-protected derivatives of 2. However, reaction of unprotected heptakis(6-deoxy-6-iodo)cyclomaltoheptaose with lithium cyanide in N,N-dimethylformamide afforded a high yield of the corresponding heptakis(6-cyano-6-deoxy) compound, i.e., cyclohepta-($1\to 4)$-(6-deoxy-$\alpha$-D-gluco-heptopyranosid)urononitrile 26, catalytic hydrogenation of which gave the title compound, cyclo-$( 1\to 4)$-(7-amino-6,7-dideoxy-$\alpha$-D-gluco-heptopyrano)heptaose 6, isolated as its peracetyl derivative 29. Section III. An approach to the synthesis of 3-deoxy-D-manno-2-octulosonic acid (KDO) 1 by the ironcarbonyl method of chain-elongation starting from methyl $\alpha$-D-mannopyranoside 2 was attempted. Reaction of methyl 2,3,4-tri-O-acetyl-6-O-p-tolylsulfonyl-$\alpha$-D-mannopyranoside 3 with sodium dicarbonylcyclopentadienyliron, followed by oxidative carbonyl insertion and hydrolysis with bromine and water, gave the methyl 2,3,4-tri-O-acetyl-6-deoxy-$\alpha$-D-manno-heptopyranosiduronic acid 5. O-Deacetylation then afforded methyl 6-deoxy-$\alpha$-D-manno-heptopyranosiduronic acid 6 in high yield. Compound 6 can also be obtained from methyl (methyl 2,3,4-tri-O-benzoyl-6-deoxy-$\alpha$-D-manno-heptopyranosid)uronate 8 by O-debenzoylation and alkaline hydrolysis of the resulting methylester 9. Acid hydrolysis of 6 gave the free hepturonic acid 10 and an unknown product. Treatment of this mixture with sodium borohydride, followed by acetylation, provided the corresponding penta-O-acetyl-2-deoxy-D-manno-heptonic acid 11.

This thesis comprises research on the regioselective carbonylation and related reactions involving various unsaturated organic substances such as alkenes, alkynes, allylic esters, alcohols and amines, open chain and cyclic $\alpha$,$\beta$-unsaturated esters using cationic, neutral and zwitterionic rhodium(I) complexes as catalysts. New methods for the preparation of valuable functionally substituted derivatives have been developed.

Studies directed towards the synthesis of the taxane skeleton is described. The synthesis and cyclopropanation of 170 was attempted, and the preparation and base induced cyclization of gamma,delta-epoxyketone 187 and gamma,delta-epoxyester 198 examined. An unusual cycloaddition of ethyl vinyl ether to ketene carbonyls to form oxetanes was uncovered. The ketenes were generated from the cyclic diazoketones 210, 211 and 213 and the acyclic system 215. In all cases, with either Rh2(OAc)4, Pd(OAc) 2 or CuCl as catalyst, the oxetanes were the major products. Irradiation afforded the cyclobutanones 236, 237, 238 and 239, while triplet sensitized photolysis afforded both oxetane and cyclobutanone. Less electron rich olefins followed literature precedent for metal catalyzed decomposition to yield cyclopropanes. These features are consistent with a zwitterionic intermediate such as 247 (Scheme i illustrates these general features). The preparation of the key radical cyclization precursor 282 and related compounds, 289 and 305 containing the taxol A and C ring models from enone 202 and subsequent radical cyclization to the taxane skeleton 284a are also described.* *Please refer to dissertation for diagrams.

Studies based on radical-induced ring openings of halolactones, spirocyclobutanones, and Rh$\sb2$(OAc)$\sb4$-catalyzed reactions of $\alpha$-diazoketones are described. Novel ring openings and subsequent decarboxylations of iodolactone 66 and bromolactone 67 to give diene 78 were found to proceed under SmI$\sb2$/THF/HMPA (4 equiv) conditions. Upon treatment of iodothialactone 63, iodolactone 66 or bromolactone 67 with SmI$\sb2$/THF/HMPA with "reverse addition" it was found that the ring-opened unsaturated acid 79 was obtained in good yield in each case. The unprecedented ring opening reactions of $\alpha$-ketospirocyclobutanes 123 and 124 with SmI$\sb2$ afforded ketones 126 and 127 in 70% and 88% yield, respectively. Dihydrofurans 217 and 224 were prepared from azibenzil (210) and $\alpha$-diazoketone 223, respectively, via Rh$\sb2$(OAc)$\sb4$-catalyzed reactions with ethyl vinyl ether. The structures of 217 and 224 were rigorously established and the former assignments were corrected. These structures (217 and 224) were unamiguously assigned by characterization of the corresponding transketalization products 222 and 226. Preliminary studies towards the preparation of the novel hydrocarbon-soluble Sm(II) complex 88 are presented. An unprecedented Grob-type fragmentation is postulated to explain the formation of benzyl alcohol from the DIBAL reduction of the donor-acceptor cyclopropane 215. Cyclopropyl alcohol 259 was also produced from this reaction. The characterization of 259 established the intermediacy of donor-acceptor cyclopropanes in the production of dihydrofurans 217 and 224, and suggests that this pathway is more general than the literature implies.$\sp*$ ftn$\sp*$Please refer to the dissertation for diagrams.

A series of quaternarized ammonium mono and di-cations, quaternarized amino acid ester mono and di-cations, and quaternarized polyammonium cations were synthesized by methylation reaction. The synthesized quaternarized ammonium derivatives were incorporated into the interlamellar space of the smectites, montmorillonite (SWy-1) and hectorite (SHCa-1). The adsorption of these quaternarized ammonium cations by the smectites were studied by colorimetric and Na-electrode methods. Also the CEC values were determined from the adsorption isotherms and were found to be close to the CECs of the smectites. The intercalation of the quaternarized ammonium cations into the interlamellar space of the smectites were evaluated by X-ray powder diffraction technique and the changes of the interlayer spacings upon intercalation were measured. The adsorption and X-ray results indicated that the quaternarized ammonium cations adopt a parallel orientation arrangement in the interlamellar space of the smectites. Insight into the micropore structure of the prepared organo-smectites has been obtained with N$\sb2$ adsorption and desorption studies. The BET interlayer surface area, external surface area, micropore volume and mesopore volume were calculated from the N$\sb2$ adsorption and desorption isotherms. The total BET surface areas of the organo-smectites were in the range of 58-224 m$\sp2$/g, depending on the size of the intercalated cations. It has been implied that the incorporation of the quaternarized ammonium cations into the interlamellar space of the smectites results in a microporous material with a network of cavities whose height and volume are controlled by the size and the shape of the organic cation. The gas chromatographic properties of these organo-smectites have been determined with focus on the separation of air, CH$\sb4$ and CO$\sb2$ as well as the separation of C$\sb1$-C$\sb4$ and C$\sb5$-C$\sb8$ hydrocarbons. The organo-smectites have been proven to be a GC adsorbent for gas separations. The separation of methane and carbon dioxide was controlled by the interactions with the clay surface, not by the interaction with the substituents of the alkylammonium chain. The shapes of the microcavities played a role in the separation of gas mixtures. The CO$\sb2$ retention time has been found to increase with increasing the free surface area of the organo-smectite. Moreover, it has been shown that the retention time of C$\sb1$-C$\sb4$ hydrocarbons decreased with increasing the free volume of the organo-smectite. Furthermore, some microporous organo-smectite materials have been imbedded into the cross-linked polydimethylsiloxane (PDMS) polymers giving composite membranes. The composite membranes have been evaluated by the gas permeation experiments. The pure gas permeation results showed that the gas permeabilities decreased upon filling of the organo-smectites into the PDMS polymers. The pure gas permeability ratios of O$\sb2$/N$\sb2$ and CO$\sb2$/CH$\sb4$ were found to be controlled by both the organo-smectite content and the microporosity of the organo-smectites. The maximum pure gas permeability ratio for CO$\sb2$/CH$\sb4$ achieved was 8.7 as compared to 3.9 which was obtained for organo-smectite free PDMS membranes.

An important class of carbonylation reactions to construct lactams are those that involve the direct "stitching" of carbon monoxide into a nitrogen heterocycle resulting in ring expansion. Cobalt carbonyl catalyzed the carbonylation of a series of 2-substituted pyrrolidines to form piperidinones. The reaction is regiospecific in most cases and the yield of product is increased when ruthenium carbonyl is present as a second catalyst. Chapter 2 of this thesis describes this piece of work. During the investigation of the ring expansion carbonylation reactions of pyrrolidines, a new rearrangement process was discovered which occurred with nitrogen heterocyclic ketones $\rm\lbrack (CH\sb2)\sb{n}NCH\sb2COR,$ n = 4-7) to give lactams in 72-93% yields, catalyzed by the dual metallic $\rm\lbrack Co\sb2(CO)\sb8/Ru\sb3(CO)\sb \rbrack$ system. Studies, including several labelling experiments, indicated a hydrogen-oxygen positional exchanging path. After rearrangement, Ru$\sb3$(CO)$\sb $ could be recovered, and no Ru-Co clusters was detected. The most probable explanation for this finding may be that some of the steps in the reaction pathway are catalyzed by ruthenium while others are more effectively catalyzed by cobalt complexes. This work is discussed in detail in Chapter 3. A novel cyclization reaction was also observed during mechanistic studies giving information on the rearrangement reaction. That is, when ketones in which only one of the hydrogen atoms at an $\alpha$-carbon atom of a nitrogen-containing heterocycle is replaced by an alkyl group (e.g. 2-methyl (or 2,6-dimethyl)piperidinyl ketones), the reaction afforded the bicyclic 5,6,7,8-tetrahydroindolizines in 72-94% yields. In contrast to the rearrangement process which requires both Co$\sb2$(CO)$\sb8$ and Ru$\sb3$(CO)$\sb $ as catalysts, Co$\sb2$(CO)$\sb8$ or Ru$\sb3$(CO)$\sb $ only could catalyze the cyclization reaction in high yields. These bicyclic products are well known precursors of many alkaloids. Reaction of 2-aryl-5,6,7,8-tetrahydroindolizines with singlet oxygen, whether generated under sensitized photoreaction conditions or by cobalt catalyzed oxidation under mild conditions, gave 2-aryl-8a-hydroxy-6,7,8,8a-tetrahydro-3(5H)indolizinones in 63-71% yield. Chapter 4 deals with these transformations. Under phase transfer catalysis conditions some five and six-membered nitrogen-containing heteroaromatics reacted with acetylcobalt tetracarbonyl, generated in situ from CO, CH$\sb3$I and dicobalt octacarbonyl. Isoxazoles or isothiazoles gave N-acylated 1-amino-2-alken-3-ones or thiones, i.e. ring-cleavage reductive acylation products. The highest stereoselectivity (Z/E: 10/1) of the acylation reaction was found in the case of 5-methylisoxazole. Under the same conditions phthalazine, quinoline and isoquinoline gave N-acylated dimers in low to moderate yields. The reactivity of several other nitrogen-containing heterocycles such as pyrazoles was also investigated and the results are summarized in Chapter 5.

The synthesis of the new thermolabile ironnitrosylhydride complex FeH(NO)(CO)(dppf) is reported. (dppf = 1,1$\sp\prime$-bisdiphenyl phosphino-ferrocene). The facile decomposition of FeH(NO)(CO)(dppf) is interpreted in terms of a homolysis of the Fe-H bond and of a nitrosyl transfer reaction. The synthesis of the structurally characterized iron complex Fe(O=PPh$\sb2$(2-Py))$\sb3\sp2\sp+\cdot$2BF$\sb4\sp-$, by the reaction of Fe(NO)$\sb2$(THF)$\sb2\sp+$ with PPh$\sb2$(2-Py) is described. The proposed mechanism for the formation of Fe(O=PPh$\sb2$(2-Py))$\sb3\sp2\sp+\cdot$2BF$\sb4\sp-$ involves a combination of disproportionation and oxygen transfer reactions. This dipositive iron complex is the first example of a first row transition metal chelated by the oxide of diphenyl(2-pyridyl)phosphines. The synthesis and the reactivity of the cobaltdinitrosyl monometallic Co(NO$\sb2$(PPh$\sb2(2$-Py))$\sb2\sp+\cdot$BF$\sb4\sp-$, Co(NO)$\sb2$(Py)$\sb2\sp+\cdot$BF$\sb4\sp-$, Co(NO)$\sb2$(Py)$\sb2\sp+\cdot$BPh$\sb4\sp-$ and bimetallic Co$\sb2$(NO)$\sb3$(PPh$\sb2$(2-Py))$\sb2\sp+$ -BPh$\sb4\sp-$ complexes are reported. The single crystal X-ray diffraction study of Co(NO)$\sb2$(PPh$\sb2$(2-Py))$\sb2\sp+$BF$\sb4\sp-$ shows that the aminophosphine ligands are co-ordinated through their P-donor sites. In solution, Co(NO)$\sb2$(Py)$\sb2\sp+$BF$\sb4\sp-$ was stable whereas, Co(NO)$\sb2$(Py)$\sb2\sp+$BPh$\sb4\sp-$ decomposed rapidly. The structural study of Co(NO)$\sb2$(Py)$\sb2\sp+$BF$\sb4\sp-$ has led to the proposal of a new theoretical model in which the non-bonded repulsions between the NO and L ligands of the M(NO)(L) moieties provide the most influential factor for fixing the value of the (O)N-M-N(O) angle. The structurally characterized Co$\sb2$(NO)$\sb3$(PPh$\sb2$(2-Py))$\sb2\sp+$ -BPh$\sb4\sp-$ complex is the first example of a bimetallic containing two metal-metal bonded first row transition metals with diphenyl(2-pyridyl)phosphine as a bridging ligand. It is also the first example of a Co$\sb2$(NO)$\sb3\sp+$ bimetallic core stabilized by two diphenyl(2-pyridyl)phosphine ligands coordinated by the P and N donor sites of the ligands arranged in a head-to-head fashion.

Chapter 1. A brief overview of the preparation and uses of o-quinodimethanes and benzocyclobutenes is presented. Chapter 2. The preparation of benzylidenebenzocyclobutene analogs from acetylenic precursors is presented. The strategy initially involves addition of tributyltin hydride to acetylenes via free-radical or palladium catalysed processes. The resulting vinylstannanes then undergo an intramolecular Stille coupling to yield benzocyclobutenes. For (o-bromoaryl)phenylalkynones, both steps were mediated by palladium catalysis, thus leading to a convenient one-pot synthesis of 2-benzylidenebenzocyclobutenones. Chapter 3. In order to overcome difficulties in scaling up the preparation of 2-benzylidenebenzocyclobutenones as described in Chapter 2, the reaction in question is examined in greater detail. Although the problems involved were not ultimately eliminated, a greater understanding of the parameters involved points to areas for further experimentation. Attempts to prepare benzocyclobutene derivatives via a double Stille coupling strategy using a vinyldistannane are then discussed. Several other miscellaneous attempts at benzocyclobutene syntheses are also investigated. Chapter 4. A proposed scheme for utilizing 2-benzylidenebenzocyclobutenones as precursors to regioisomeric anthraquinones is presented. The key step in this scheme involves oxidative removal of the benzylidene functionality. Although this transformation was not successful, an interesting rearrangement is found to occur upon ozonolysis of various benzylidenebenzocyclobutene derivatives. Complete assignment of the $\sp $C and $\sp1$H NMR resonances of one of these rearrangement products is described using the FLOCK pulse sequence. Chapter 5. The thermolysis of aryl, vinyl and alkynyl benzylidenebenzocyclobutenols is described. Oxidative removal of the benzylidene functionality after thermolytic ring expansion of the phenyl and vinyl precursors provides anthraquinone and naphthoquinone, respectively. Chapter 6. The anionic cleavage of several benzylidenebenzocyclobutenols is presented. The stereochemistry of the benzylidene group is used as a mechanistic probe to differentiate between a carbanionic and an electrocyclic pathway for the opening of the cyclobutene ring. For all derivatives studied, the carbanionic mechanism is shown to operate. The Z to E isomerization of lithium benzylidenebenzocyclobutenoxide is postulated to proceed via a carbanionic ring opening-vinyl anion isomerization-ring closure sequence. Trapping of the putative aldehyde intermediate with excess methyl lithium supports this mechanism. Chapter 7. The photoisomerization and photodimerization of benzylidenebenzocyclobutenones is discussed. Trapping studies and laser flash photolysis experiments point to the involvement of a ketene-allene as a major intermediate in the isomerization process. Chapter 8. A method is described which allows visualization of column chromatography by use of a quartz column and addition of a fluorescent indicator to commercial adsorbents.