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

Rhenium-catalyzed stereoselective transposition of allylic alcohols is reported. In the presence of 1 mol% of Re2O7, (E)- or (Z)-& delta;-hydroxymethyl-anti-homoallylic alcohols were converted into the acetals of 2-methyl-1,3-syn-diols with excellent diastereoselectivities. 1,3-syn-Diol acetals can also be synthesized from (E)-& delta;-hydroxymethyl-syn-homoallylic alcohols.

Automated summary

A Rhenium-catalyzed stereoselective transposition of allylic alcohols is described. In the presence of 1 mol% of Re2O7, (E)- or (Z)-δ-hydroxymethyl-anti-homoallylic alcohols were converted into the acetals of 2-methyl-1,3-syn-diols with excellent diastereoselectivities. 1,3-syn-Diol acetals can also be synthesized from (E)-δ-hydroxymethyl-syn-homoallylic alcohols.