Organocatalytic Formation of Chiral Trisubstituted Allenes and Chiral Furan Derivatives.

A novel reaction that provides chiral allenes by amino catalytic activation of either aldehydes or α,β-unsaturated aldehydes for reaction with alkynyl-substituted enones is presented. The reaction forms a variety of trisubstituted allenes in high yields and with excellent stereoselectivities. The utility of the reaction concept is demonstrated by the synthesis of chiral furan derivatives in high yields and stereoselectivities.