Zinc-catalyzed asymmetric [3 + 2] annulations for the construction of chiral spiro[1-indanone-γ-butyrolactones] via a C–N bond cleavage process

Abstract

An intriguing tandem Michael/lactonization reaction of α-hydroxy-1-indanones and methyleneindolinones has been established in this work. The employment of chiral dinuclear zinc catalysts is essential in achieving highly efficient chirality transfer and realizing the intramolecular amide C–N bond cleavage via a Brønsted base and Lewis acid cooperative activation model. This [3 + 2] annulation gives access to a broad range of optically pure spiro[1-indanone-γ-butyrolactone] derivatives in good yields with excellent levels of diastereoselectivities and enatiostereoselectivities (up to 75% yield, 20 : 1 dr, and 98% ee).