Stereoselective syntheses of 2-methyl-1,3-diol acetals Re-catalyzed [1,3]-allylic alcohol transposition.

Rhenium-catalyzed stereoselective transposition of allylic alcohols is reported. In the presence of 1 mol% of ReO, ()- or ()-δ-hydroxymethyl--homoallylic alcohols were converted into the acetals of 2-methyl-1,3--diols with excellent diastereoselectivities. 1,3--Diol acetals can also be synthesized from ()-δ-hydroxymethyl--homoallylic alcohols.