Asymmetric Diels–Alder reactions between chiral sugar nitroalkenes and 1-O-substituted buta-1,3-dienes. Synthesis and reactivity of new cyclohexenyl derivatives

Abstract

Uncatalysed Diels–Alder reactions between 1-(trimethylsiloxy)- or 1-acetoxy-buta-1,3-diene and sugar-derived nitroalkenes having D-galacto or D-manno configurations proceeded with complete regioselectivity. Diastereofacial specificity was also complete with the D-galacto dienophile, whereas it was only moderate with the D-manno. With 1-acetoxybuta-1,3-diene, interaction between reactants took place exclusively in the endo mode. Starting from cycloadducts, a series of highly functionalised chiral compounds have been prepared, their conformations and stereochemistries being investigated.