Practical synthesis of homopropargylic and allenic alcohols

Abstract

In this thesis, a study of indium-mediated regioselective, enantioselective propargylation and allenylation was carried out.A novel method for allenylation and propargylation of aldehydes was accomplished. By just changing the silyl groups and the reaction conditions, both the allenic and homopropargylic alcohols can be obtained in high regioselectivities.Asymmetric indium-mediated propargylation of aldehydes using (-)-cinchonidine, (+)-cinchonine and (S,S)-2,-6,-bis-(4-isopropyl-2-oxazolin-2-yl)pyridine as the chiral sources was successfully accomplished. The indium-mediated asymmetric allylation and propargylation of trifluoroacetaldehyde ethyl hemiacetal and bromal gives desired products in moderate to good enantioselectivities.Different allenic alcohols can be converted to their corresponding propargylic alcohols in the presence of the corresponding parent aldehydes. Crossover reactions with various aldehydes were conducted to prove that this conversion involves an aldehyde.These findings extend the scope on the use of homopropargylic and allenic alcohols in organic synthesis.