A collection of 4,10-chrysene derivatives was prepared via the BHQ (Bull-Hutchings- Quayle) reaction, their electronic and morphological properties analysed and assessed for suitability as organic semiconductor (OSC) materials. Larger polycyclic aromatic hydrocarbons (PAHs) such as benzo[k]tetraphenes and dinaphtho[1,2,-b:1',2'- k]chrysenes were then prepared and similarly characterised. An acene-based OSC material TMTES-pentacene was also prepared. It is proposed that non-linear PAH- based OSC materials may provide an alternative to popular acene-based materials; offering advantages in stability, diversity and handling.

The Bull-Hutchings-Quayle (BHQ) reaction is a novel method for the synthesis of 1-(bromo/chloro)napthalenes from 2-allyphenyl-2’,2’,2’-tri(bromo/chloro)acetates. The reaction is also known as Atom Transfer Radical Cyclisation-Benzannulation (ATRC-Benzannulation). The ATRC-Benzannulation of structurally diverse 2-(cyclohex-1-en-1-ylmethyl)phenyl 2’,2’,2’-trichloroacetates in the presence of 1,3bis-(2,6diisopropylphenyl)imidazolium copper(I) chloride [“Nolan NHC-CuCl”] complexes, using microwave or thermolytic methods, afford a range of 9-chloro-1,2,3,4-tetrahydroanthracenes. Efficient ATRC-Benzannulation has been restricted to microwave conditions so a thermolytic method has been developed as an alternative. Application of BHQ methodology toward the synthesis of the core structure of lactonamycin are reported. Stille, Suzuki and Sonogashira cross-coupling methods were used for the synthesis of diene precursors of a lactonamycin analogue. [4+2] Diels-Alder cycloadditions have been investigated with the diene precursors and various dienophiles. 1-Chloroquinone has been displaced with para-methoxyphenol to generate 1-para-methoxyquinone. CAN mediated oxidation of 1-para-methoxyquinone has yielded 1-hydroxyquinone.

(3aR)-14a-Acetoxy-3aß,4,14,14aa-tetrahydro-6,7,8-trimethoxybenzo[3,4]furo[3',4':6,7]cycloocta[1,2-f][1,3]benzodioxol-3(1H)-one (steganacin), 56, has been a popular synthetic target due to its perceived cytotoxic activity. Our proposed strategy for the construction of the key 8-membered ring embedded within steganacin was via an oxidative phenolic coupling of an appropriate (3R,4R)-4-(benzo[d][1,3]dioxol-5-ylmethyl)-3-benzyldihydrofuran-2(3H)-one analogue which were shown to be readily available from commercially available piperonal in six linear steps involving chain extension, reduction, trichloroacetylation and cyclisation via a copper-catalysed Atom Transfer Radical Cyclisation (ATRC) reaction. In this way, copper-catalysed ATRC reaction of (E)-6-(benzo[d][7’,9’]dioxol-1’-yl)allyl-1,1,1-trichloroacetate afforded (R)-4-{(R)-benzo[d][1,3]dioxol-5-ylchloromethyl}-3,3-dichlorodihydrofuran-2(3H)-one in good isolated yield as a mixture of diastereosiomers. Regiospecific functionalisation of these trihalides at the benzylic position (via an SN1, solvolysis, pathway), followed by dehalogenatioin and subsequent enolate alkylation afforded the key butyrolactone intermediates whose oxidative cyclisation was the key bond construct in our approach to steganacin. Contrary to our expectations it was observed that these substrates suffer intramolecular Friedel-Crafts alkylation reactions, favouring a 3a,4,9,9a-tetrahydronaphtho[2,3-c]furan-1(3H)-one (6 member ring) formation, rather than phenolic oxidative coupling reactions that would favour the steganacin-like (3aR,11aR,Z)-3a,4,11,11a-tetrahydrobenzo[4,5]cycloocta[1,2-c]furan-1(3H)-one (8 member ring) formation, when the oxidant has any Lewis acid capacity. Taking these observations into account we believe that by judicious choice of synthetic route the ATRC chemistry developed during the current research could be applied to a highly convergent (9 step) route to the synthesis of deoxypodophylotoxin.This work also describes, in detail, the efforts of this worker to establish and optimise a robust route that potentially can lead to the formation of steganacin via the alternative route of an initial microwave-assisted Pd-mediated biaryl coupling of either bromopiperonal or an halogenated derivative of the described γ-butyrolactones with an appropriate boronic acid derived from commercially available 3,4,5-trimethoxybenzalcohol to afford the biaryl scaffold present in steganacin. The completion of this synthesis was unfortunately left unaccomplished due to time constraints.

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