Haloaldehyde Polymers XXXIII. Polymerization of Chloral with Chiral Anionic Initiators. Stereochemistry of Initiation

Abstract

The addition of trichloroacetaldehyde (chloral) to an equimolar amount of the lithium alkoxide of (−)borneol gave, after acetylation with acetic anhydride, diastereomers which were separated by gas chromatography. The products resulted from meso and racemic addition of the (−)borneoxide on chloral. Di-addition products with two chloral residues were also isolated but the individual isomers were not identified. Similar studies with the alkoxides of racemic alcohols were also undertaken. An analysis of their addition products suggested that the individual (R) and (S) components of the chiral alkoxides added chloral in a stereochemically preferred manner. This preference was most pronounced for those alkoxides which possess a high degree of steric bulk around their chiral carbon atoms.