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The generation of 1-bromo and 1-chloroalkyl radicals from organoboranes has been investigated. The direct approach involving the hydroboration of halogenated alkenes is impeded by partial dehalogenation taking place during the hydroboration process. An indirect method involving the generation of B-(1-chloroalkyl)catecholborane by homologation of B-alkylcatecholborane with dichloromethyllithium was developed. A reaction sequence involving a hydroboration reaction, a Matteson homologation, and a radical allylation process has been performed as a one-pot process that takes advantage of three different reactivities of organoboron species. Starting from styrene derivatives, it was possible to prepare B-(1-chloro-2-arylpropyl)catecholboranes that are excellent precursors to 1-chloro-2-arylpropyl radicals. A concise approach for the synthesis of an optically active α-methylene-γ-lactone from p-chlorostyrene has been developed on the basis of a two-step sequence involving an enantioselective hydroboration-homologation-cyclization reaction followed by a hydrolysis-lactonization process.

A practical procedure for the palladium-catalysed Suzuki–Miyaura coupling of various alkenyl tosylates with alkenyl MIDA boronates has been developed. Commercially available trans -bromo[ N -succinimidyl-bis(triphenylphosphine)]palladium(II) [Pd(PPh 3 ) 2 NBS] is an effective catalyst under the slow release conditions of MIDA boronates; with less activated alkenyl tosylates addition of the cheap, air-stable tricyclohexylphosphine tetrafluoroborate enhances reactivity.

Generation of radicals from B-alkylcatecholboranes represents an efficient tin-free procedure for the generation of alkyl radicals. A modified version of this method has been developed. The simple catechol is replaced by a dihydroxylated tetrahydroisoquinoline, which can be separated from the reaction products by simple extraction with an aqueous acid solution. The modified alkyl radical precursors are easily prepared from alkenes by hydroboration with BH3 center dot Me2S followed by treatment with the dihydroxytetrahydroisoquinoline. The new alkylboronates of this type are suitable radical precursors in a wide range of reactions such as sulfenylation, allylation, alkynylation, vinylation, and addition to quinones. This strategy is particularly useful when separation of reaction products from catechol residues is problematic, as illustrated by a radical addition to 1,4-benzoquinone leading to 2-alkyl-1,4-hydroquinones.

Synthetic routes to six 3-D scaffolds containing piperazine, pyrrolidine and piperidine cores have been developed. The synthetic methodology focused on the use of N -Boc α-lithiation-trapping chemistry. Notably, suitably protected and/or functionalised medicinal chemistry building blocks were synthesised via concise, connective methodology. This represents a rare example of lead-oriented synthesis. A virtual library of 190 compounds was then enumerated from the six scaffolds. Of these, 92 compounds (48%) fit the lead-like criteria of: (i) −1 ⩽ A log P ⩽ 3; (ii) 14 ⩽ number of heavy atoms ⩽ 26; (iii) total polar surface area ⩾ 50 A 2 . The 3-D shapes of the 190 compounds were analysed using a triangular plot of normalised principal moments of inertia (PMI). From this, 46 compounds were identified which had lead-like properties and possessed 3-D shapes in under-represented areas of pharmaceutical space. Thus, the PMI analysis of the 190 member virtual library showed that whilst scaffolds which may appear on paper to be 3-D in shape, only 24% of the compounds actually had 3-D structures in the more interesting areas of 3-D drug space.

The reaction of tetranitromethane with B-alkylcatecholboranes leads to the formation of unusual dinitrooxime ethers. A tentative mechanism is provided, which suggests the involvement of extremely fast addition of alkyl radicals to tetranitromethane. The substitution of one of the nitro groups in the oxime ethers by nucleophiles (such as secondary amines, halogens and styrene) and by radicals generated from B-alkylcatecholboranes is reported.