ASYMMETRIC INDUCTION IN THE COUPLING OF 5,6-DIHYDRO-1,4-DITHIINS WITHCHIRAL ALDEHYDES - A NEW SYNTHETIC APPROACH TO POLYHYDROXYLATED COMPOUNDS

A new strategy is designed to synthesize polyhydroxyl compounds (and/o r carbohydrates) by coupling of 5,6-dihydro-1,4-dithiins - carrying a vinylic hydrogen atom - with chiral aldehydes and, in sequence, stereo selective removal of the dithiodimethylene dithiin bridge and stereosp ecific hydroxylation of the resulting polyhydroxyl alkenes. In this pa per the study of both coupling and desulfurization steps is reported b y the use of 2-phenyl-5,6-dihydro-1,4-dithiin (5) as a model compound in the reactions with three chiral aldehydes, 3a,b and 4. Copyright (C ) 1996 Elsevier Science Ltd.