The chemistry of organoborates. Part 6. Alkylation of alkynylborates with some complex alkylating agents
Abstract
The reactions of α-bromo-ketones, ethyl α-bromoacetate, iodoacetonitrile, and prop-2-ynyl bromide with alkynyl-trialkylborates are regio- and stereo-specific. Oxidation of the intermediate vinylboranes gives 1,4-diketones and γ-oxo-esters, -nitriles, and -alkynes. Hydrolysis of the intermediates is a stereospecific route to trisubstituted olefins of defined configuration bearing various functional groups suitable for further elaboration.