Stereodivergent (3+2)-cycloaddition of donor-acceptor cyclopropanes and citral imines catalyzed by Yb(NTf2)3/PyBOX

Abstract

The idea of (3+2)-construction of pyrrolidines is realized on the basis of a common natural substrate modified in a single position with functional groups as switches of diastereoselectivity mode. In this work, Lewis acid complex-catalyzed (3+2)-cycloaddition reactions involving donor-acceptor cyclopropanes (DACs) and newly obtained citral imines were investigated and optimized. Based on the results obtained, a method for the diastereoselective synthesis of substituted 2,5-cis- and -trans-pyrrolidines was developed. Our approach demonstrates broad substrate scope and significant synthetic utility as evidenced by directed product derivatization. This work expands the applicability of the known method to a wider range of aliphatic substrates due to the decisive participation of Yb(NTf2)3/PyBOX as a catalyst.