Phosphine-Mediated Synthesis of Oxygen-Containing Heterocycles

Significance

Relatively few examples of highly enantioselective phosphine-catalyzed transformations have been reported to date. The authors ­investigate an enantioselective variant of an intra-molecular γ-addition of oxygen nucleophiles to alkynoates, first reported by Trost and Li (J. Am. Chem. Soc. 1994, 116, 10819). A moderate scope to form saturated furans and pyrans with good enantioselectivities and yields is reported.