SYNTHESIS OF ASYMMETRICALLY DEUTERATED GLYCEROL AND DIBENZYLGLYCERALDEHYDE VIA BORONIC ESTERS

(S)-Pinanediol [(benzyloxy)methyl]boronate (la) has been converted via an improved procedure to (S)-pinanediol (1 R)- [1,2-bis(benzyloxy)ethyl]boronate (3a) (96% de), which with (dibromomethyl)lithium has yielded (S)-pinanedio! (1 S,2S)-[2,3-benzyloxy)-1 -bromopropyl]boronate (4Da). Treatment with potassium triisopropoxyborodeuteride has yielded (S)-pinanediol (1R,2R)-[2,3-bis(benzyloxy)propyljboronate-1-d (5Da), which on deboronation with hydrogen peroxide and debenzylation has yielded (1S,2S)-glycerol-1-d (7D) in ~92-94% de. The opposite diastereomer, (1R,2S)-glycerol-1 -d (7L), was obtained via 3a with (dibromomethyl)lithium-d and reduction of the resulting (S)-pinanediol (1S,2R)-[2,3-bis(benzyloxy) propyl]boronate-1-d (5La) with lithium triethylborohydride. Chain extension of (S)-pinanediol (p-methoxybenzyl)boronate (lb) via the alcohols 6b, benzylation to 8b, and DDQ cleavage of the methoxybenzyl group to form alcohols 8c followed by Swern oxidation has led to dibenzyl-(2R,3S)-glyceraldehyde-3-d (9D) and dibenzyl-(2R,3R)-glyceraldehyde-3-d (9L). Conversion of 8c to the crystalline trityl ether 8d reveals that deuterium label placement is in ≥98% absolute configurational excess, and the major diastereomeric contaminant (2-3%) of the glyceroW is in error at C(2). © 1990, American Chemical Society. All rights reserved.