Copper-Catalyzed Asymmetric Diyne Cyclization via [1,2]-Stevens-Type Rearrangement for the Synthesis of Chiral Chromeno[3,4-c]pyrroles

Here, we report a copper-catalyzed asymmetric cascade cyclization/[1,2]-Stevens-type rearrangement via a non-diazo approach, leading to the practical and atom-economic assembly of various valuable chiral chromeno[3,4-c]pyrroles bearing a quaternary carbon stereocenter in generally moderate to good yields with wide substrate scope and excellent enantioselectivities (up to 99 % ee). Importantly, this protocol not only represents the first example of catalytic asymmetric [1,2]-Stevens-type rearrangement based on alkynes but also constitutes the first asymmetric formal carbene insertion into the Si-O bond.

Automated summary

In this study, a copper-catalyzed asymmetric cascade cyclization/[1,2]-Stevens-type rearrangement was reported to efficiently assemble a variety of valuable chiral chromeno[3,4-c]pyrroles bearing a quaternary carbon stereocenter with generally moderate to good yields and excellent enantioselectivities (up to 99% ee). Notably, this protocol represents the first example of catalytic asymmetric [1,2]-Stevens-type rearrangement based on alkynes and the first asymmetric formal carbene insertion into the Si-O bond.