BDTBPMB has been proven to be an essential ligand in carbonylation chemistry. Its two tert-butyl groups and wide bite angle give it the ideal characteristics for this kind of chemistry, and leads to high activity and selectivity with use of its complexes. During this work the group of reactions where this ligand has been proven to be active has been extended with two new protocols for hydroxycarbonylation and aminocarbonylation. In the hydroxycarbonylation process, a large variety of unsaturated compounds were studied. Dioxane was found to be the ideal solvent, due to its properties in terms of coordinability, and miscibility with water. Using this solvent as the medium, a BDTBPMB complex of palladium was found to be highly active and selective under mild conditions. Initial attempts to address the aminocarbonylation of alkenes catalysed by the Pd/BDTBPMB system did not give high activity. This problem was overcome by the addition of an arylalcohol. Under those conditions, high selectivity and conversion was obtained in a wide variety of amides. However, attempts to address the aminocarbonylation of alkenes with ammonia gas to generate primary amides did not result in any conversion. The generation of these primary amides was obtained with transamidation of N-phenylnonamides which can be prepared by aminocarbonylation. Amides have been successfully hydrogenated to amines catalysed by a Ru/Triphos system. This system has been proven to be highly active in this reaction. High selectivities have been obtained in the generation of secondary amine. However, initial results of the hydrogenation of primary amides resulted in no formation of primary amines. A careful analysis of the mechanism of the formation of various products from the hydrogenation of primary amides allows the selective formation of primary amines by the ruthenium/Triphos system in the presence of ammonia. The possibility of the generation of primary amides in situ from acids under hydrogenation conditions, giving primary amines was explored with high conversion and moderate selectivities. To complete this work, a system based on a palladium complex for the decarboxylation of benzoic acids was developed. Usually, the decarboxylation reactions catalysed by copper require high temperatures. However, palladium complexes of highly electron donating ligands such as BDTBPMB or P([superscript]tBu)₃ were found to be highly active under milder conditions. This catalytic system was proven to be active in desulfonation reactions giving high conversion.

published_or_final_version / Chemistry / Doctoral / Doctor of Philosophy

published_or_final_version / Radio Chemistry / Master / Master of Philosophy

published_or_final_version / Chemistry / Doctoral / Doctor of Philosophy

published_or_final_version / Chemistry / Doctoral / Doctor of Philosophy

M.Sc. (Chemistry) / Please refer to full text to view abstract

We report here the development of new and more general synthetic pathways for the preparation of allenyl and alkynyl carbonyls. These highly dense functionalized compounds were utilized as key intermediates for the synthesis of [3.2.1] and [3.3.1] bicyclic framework, the motifs found in many natural products. A convenient method described for the dehydration of ketoesters to generate conjugated and deconjugated alkynyl esters and conjugated allenyl esters. This sequential one-pot method involves the formation of a vinyl triflate monoanion intermediate that leads to the selective formation of alkynes or allenes depending on additives and conditions used. Product outcomes appear to be a function of unique monoand dianion mechanisms which are described. Our design of a Morita-Baylis-Hilman (MBH) reaction to include a fast silyl 1,3- Brook rearrangement has enabled the first ever anion-catalysis. This new reaction makes possible the addition of both aliphatic and aromatic aldehydes to s ilylallenes leading to carbinol allenoates. These new MBH reactions products allow for a fasttracked synthesis of [3.2.1] bisoxa-bicycles which make up the framework of many biologically active natural products including Vitisinol D. The development of cyclic addition of hydrazine nitrogen to unactivated alkynes catalyzed by non-metals is reported. Starting from readily accessible silyl allenyl esters, alkynyl hydrazines are prepared in one step and subsequently undergo unprecedented cyclization reactions in the presence of ammonium and phosphonium catalysts leading to dehydro-azaproline products. These heterocycles were also produced in high enantiomeric excesses using chiral ammonium phase transfer catalysts via a kinetic resolution pathway. / The racemic synthesis of fully functionalized bicyclic core of Vitisinol D was achieved using allenyl ester as a key intermediate. The required electron withdrawing group (EWG) at the position was screened for better addition followed by the compatibility towards successive transformation and, finally, the ease of removal. A reductive aldol method to transform lactone-enol to the desired [3.2.1] bicycle was extensively studied to understand the stereoelectronic requirements for the formation of such bicyclic structures. Due to the necessity of selective protection and deprotection of many phenolic and aliphatic hydroxyls as well as ester groups, orthogonal protecting groups were established accordingly. / by Pradip Maity. / Thesis (Ph.D.)--Florida Atlantic University, 2011. / Includes bibliography. / Electronic reproduction. Boca Raton, Fla., 2011. Mode of access: World Wide Web.

Since late 1990s, organocatalysis has been widely explored in many aspects and achieved various difficult transformations. In this field, carbonyl catalysis, which could be traced back to 1860 has been developed with impressive progress including asymmetric variants. Over the years, major activation modes were developed for carbonyl catalysis including exploiting temporary intramolecularity to form catalytic tethers and transient intramolecular nucleophiles, dioxirane formation and imine formation. On the other hand, electrophilic activation is also an important area of organocatalysis where impressive progress has been achieved. However, limited examples were reported to achieve the electrophilic activation via carbonyl catalysis. Organophosphorus compounds are crucially important in many aspects in organic chemistry. Many approaches were developed for asymmetric organophosphorus compounds. In this work, different types of organophosphorus compounds were used as the substances for aldehyde-catalyzed hydrolysis reactions. The first part of this thesis illustrated the strategy to combine carbonyl catalysis and electrophilic activation. The hydrolysis of organophosphorus compounds containing P(=O)-N bond were investigated based on Jencks and Gilchrist’s preliminary results with formaldehyde as the catalyst to promote the hydrolysis of one inorganic substance, phosphoramidate. This Chapter describes a systematic research to identify a superior catalyst, o-phthalaldehyde, and develop catalytic hydrolyses of various organophosphorus compounds containing P(=O)-NHR subunits. Gratifyingly, the reaction proved efficient with phosphinic amides and phosphoramidates. Moreover, chemoselectivity was also studied and selective hydrolysis of the P(=O)-N bonds in the presence of P(=O)-OR bonds could be accomplished. The second part of this thesis demonstrated the further development of one of the major modes of carbonyl catalysis. Formaldehyde was identified as the efficient catalyst to react with α-amino phosphonates to form the transient intramolecular nucleophile, which facilitated the subsequent hydrolysis reactions. In this Chapter, different primary and secondary α-amino phosphonates with phenol as the leaving group, were tested in the reaction conditions. As a result, a vast of mono esters of α-amino phosphoric acids could be formed as the products. Finally, the last portion of this thesis applied the methodologies developed in Chapter 2 to prebiotic chemistry. A prebiotic-related aldehyde, glycolaldehyde was studied as the catalyst for the hydrolysis of organophosphorus compounds containing P(=O)-N bond, including phosphinic amides and phosphoramidates. Additionally, other prebiotic important substances, diamidophosphate (DAP) and monoamidophosphate (MAP) were also investigated for potential glycolaldehyde-catalyzed phosphorylation reaction under aqueous conditions. In the presence of catalytic amount of glycolaldehyde, 1) when water was used as the nucleophile, the hydrolysis of DAP and MAP were significantly improved; 2) when other phosphate nucleophiles were added to compete with water, DAP could act as a phosphorylating reagent to phosphorylate other phosphate nucleophiles. Overall, the results presented in this thesis investigated two different activation modes, electrophilic activation and transient intramolecular nucleophiles, for carbonyl catalysis to hydrolyze different organophosphorus compounds, phosphinic amides, phosphoramidates and α-amino phosphonates. The application of carbonyl catalysis to prebiotic chemistry was also achieved especially with the phosphorylation reaction with DAP.

The vibrational frequencies of atom to atom bonds within a molecule are a function of the bond energies. Each bond has its characteristic frequency, and most of these frequencies can be detected with the infrared spectrophotometer. When one compound reacts with another or is adsorbed on the surface of a solid, detectable frequency changes or shifts may occur. These changes or shifts yield valuable information about the bonds which are formed or broken.

This thesis presents an investigation of carbonyl sulphide as a new fumigant and related methodology studies. The first part involved the investigation of a new fumigant - carbonyl sulphide, which has the potential to replace methyl bromide. Its biological response or activity was investigated, e.g. toxicity to target organisms and phytotoxicity, environmental and worker safety considerations. In the second investigation, analytical methods were developed for the determination of fumigant movement through timber and fumigant residues in grains as well as a method of chemical fractionation to determine the fate of carbonyl sulphide. A comprehensive literature review of 161 references in these two areas is reported. Carbonyl sulphide was highly toxic to adults of three coleopteran species tested, namely Rhyzopertha dominica (F.), Tribolium confusum du Val, and Sitophilus oryzae (L.), the most sensitive species was R. dominica. For 6 hr exposure at 25�C, the L(CxT)95 value for R. dominica, S. oryzae and T. confusum were, respectively, 36.48, 99.82 and 113.0mg h L-1. Carbonyl sulphide inhibited 100% of mould in wet wheat and more than 90% of mould on dry wheat at lOOmg L-1. Both carbonyl sulphide and hydrogen cyanide were low in phytotoxicity without affecting germination of wheat, at levels needed to control insects. Unlike hydrogen cyanide, carbonyl sulphide can be used at minimum levels without decreasing plumule length of wheat. Chemical data on the sorption of carbonyl sulphide are compared with data from methyl bromide. The levels of carbonyl sulphide in the headspace of five commodities (wheat, barley, paddy, sorghum and peanut) and timbers (hardwood and softwood) decay more slowly than do levels of methyl bromide. Carbonyl sulphide was blown through a column of wheat as easily as was phosphine and more easily than was methyl bromide, and its front was blown out faster than phosphine and methyl bromide. Movement of two fumigants (methyl bromide and carbonyl sulphide) through, and sorption on, softwood and hardwood were studied. Each fumigant was sorbed less on softwood than on hardwood and penetrated softwood better than hardwood. Carbonyl sulphide penetrated timber better than did methyl bromide, and was less sorbed on timber. A rapid method of solvent extraction was developed to enable rapid estimation of the amount on intact fumigant sorbed in wood. This procedure enabled near quantitative recovery of methyl bromide as either intact fumigant or as bromide ion. Carbonyl sulphide residue in unfumigated wheat was found to be around 25- SOppb. Carbonyl sulphide left little residue on fumigated grains. Desorption of carbonyl sulphide from the wheat was extremely fast, 85% of it was released after one day aeration which was very much greater than that of methyl bromide and carbon disulphide. After 6 days aeration the incorporation of 14COS on mungbean, wheat, paddy, rice and safflower was lower than 7Oppb (calculated as COS equivalent). Food value or nutritional quality of foodstuffs is not harmed by carbonyl sulphide fumigation. This result was assessed by identifying any nonreversible change or combined residues in biochemical fractions of commodities including lipids, protein, amino acids, carbohydrate, etc., and no irreversible reaction between carbonyl sulphide and any constituent such as B vitamin, atocopherol, lysine, maltose and starch. Fumigants did not affect lipids, although each fumigant was applied to wheat at exaggerated concentrations, nor wheat germ oil and canola oil treated with extremely high concentration of fumigants. Factors which affect analysis of fumigants including stability of chemicals in extraction solvent and partitioning of fumigant between solvent and air, were examined. The partition ratio, defined as the fumigant concentration in extraction solvent to that in the headspace, varied with fumigant. Methods for multi-fumigant analysis were developed or modified and gave high recoveries and efficiency. The procedure of Daft of solvent extraction followed by partitioning was modified by being performed in sealed flasks. This raised the recovery of carbonyl sulphide, methyl bromide, phosphine and carbon disulphide. Recoveries were near quantitative at levels down to 6-16ppb (w/w) for tested fumigants. Thus the modified Daft method can be adapted to enable determination of the main fumigants used on staple foodstuffs. Microwave irradiation method give higher efficiency of removal of fumigants from grains. Limits of quantification were < 0.2ng g-1 (ppb w/w) for each tested fumigant. The detection limit of COS was calculated, as natural levels of the fumigant were detected in commodities. These are feasible, simple and rapid (< 2 min.) to be use to analyse fumigant residue in grains. Carbonyl sulphide has potential as a fumigant for grain and timber and may replace methyl bromide in some uses, subject to further investigation in commercial situations.