Homologation Strategy for the Generation of 1-Chloroalkyl Radicals from Organoboranes

The Journal of Organic Chemistry
Gong XuPhilippe Renaud

Abstract

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.

References

Jun 19, 2003·Angewandte Chemie·Arnaud-Pierre Schaffner, Philippe Renaud
Aug 5, 2006·Angewandte Chemie·Arnaud-Pierre SchaffnerPhilippe Renaud
Aug 3, 1945·Science·M S KharaschW H Urry
Nov 26, 2009·Chemical Record : an Official Publication of the Chemical Society of Japan ... [et Al.]·Jean-Pierre LepoittevinElena Giménez-Arnau
Feb 24, 2011·Journal of the American Chemical Society·Giorgio VillaPhilippe Renaud
Jul 24, 2014·Nature Chemistry·Dale J WilgerDavid A Nicewicz

❮ Previous
Next ❯

Related Concepts

Related Feeds

Allogenic & Autologous Therapies

Allogenic therapies are generated in large batches from unrelated donor tissues such as bone marrow. In contrast, autologous therapies are manufactures as a single lot from the patient being treated. Here is the latest research on allogenic and autologous therapies.