| The chiral 1,3-diol is an important structural feature commonly found in a wide variety of natural products and biologically pharmaceutical agents.The development of methodology for constructing chiral 1,3-diols and their derivatives is a significant task in the field of asymmetric catalysis.The common approach to access chiral 1,3-diols is asymmetric aldol-directed reduction transformations.However,the method can only afford chiral diols which contain primary alcohols or secondary alcohols but tertiary alcohols.Therefore,it’s necessary to develop new strategies to construct chiral tertiary 1,3-diols and their derivatives.Transition metal-catalyzed asymmetric allylic substitution of allylic donors with O-nucleophiles is a powerful tool for the construction of tertiary alcohols and their derivatives.Our group reported palladium-catalyzed asymmetric decarboxylative cycloaddition of vinylethylene carbonates with formaldehyde,which could afford a series of chiral tertiary 1,2-diols in high yields with excellent enantioselectivities.Based on previous research results,we envisioned that the same concept could be exploited to the construction of chiral tertiary 1,3-diols and their derivatives by reasonable substrate design.This research disclosed an efficient method for enantioselective construction of chiral 4-substituted-4-vinyl-1,3-dioxanes via palladium-catalyzed cycloaddition of vinyloxetanes（VOs）with formaldehyde.The reactions proceeded smoothly in the presence of Pd2（dba）3.CHCl3 and ligand（S,R,R）-L2 under mild conditions to afford 4-substituted-4-vinyl-1,3-dioxanes in high yields（up to 94%）with excellent enantioselectives（up to>99%）.The 4-substituted-4-vinyl-1,3-dioxanes could be conveniently converted to chiral tertiary 1,3-diols which are important building blocks for bioactive compounds.This reaction provides a novel method for the asymmetric synthesis of chiral 1,3-diols and their derivatives. |
