Regio- and Enantioselective Organocascade Michael- Michael Reactions: Construction of Chiral Trisubstituted Indanes

Given the importance of indane derivatives in both organic and medicinal chemistry, the development of an effective synthetic protocol for the preparation of multifunctionalized 1,2,3-trisubstituted indane derivatives is of considerable interest. In this paper, we developed a cascade regio- and enantioselective double Michael addition to construct challenging multifunctionalized chiral indane derivatives in the presence of a bifunctional acid-base organocatalyst. The resulting optically active indane derivatives with three alternating trans stereocenters were produced in moderate to good yields with excellent diastereoselectivities and excellent enantioselectivities. Remarkably, the resulting products were facilely converted into multifunctionalized optically active (1-indanylmethyl)amine and tetrahydroindeno[2,1-b]pyrrole derivatives.