Univocal syntheses of 2- and 3-hydroxymethyl-2,3-dihydro[1,4]dioxino[2,3-b]pyridine enantiomers

The enantiomers of 2- and 3-hydroxymethyl substituted 2,3-dihydro[1,4]dioxino[2,3-b]pyridine, important chiral building blocks for the prepn. of several biol. active compds., were synthesized. The resp. enantiomers were obtained benzyl glycerol and (isopropylidene)glycerol, resp. The novel efficient synthetic strategies, which do not follow routes already reported for the corresponding racemates, ensure very high regioselectivity and maintenance of the enantiomeric purity of the starting materials. The enantiomeric compn. of the title compds. was detd. by chiral HPLC or NMR. The key intermediate in the synthesis of the non-racemic title compd., namely 1-benzyl-2-mesyl-3-(trityl)glycerol, is a new high melting chiral C3 synthon, worth considering for its stability, versatility, easy isolation by simple crystn. and, potential of configuration inversion through a simple one-pot reaction sequence.