Copper‐Catalyzed Asymmetric Diyne Cyclization via [1,2]‐Stevens‐Type Rearrangement for the Synthesis of Chiral Chromeno[3,4‐<i>c</i>]pyrroles
Feng‐Lin Hong, Chong‐Yang Shi, Pan Hong, Tong‐Yi Zhai, Xin‐Qi Zhu, Xin Lü, Long‐Wu Ye
Abstract
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.
Topics & Concepts
StereocenterDiazoChemistryCatalysisEnantioselective synthesisSubstrate (aquarium)CarbeneQuaternary carbonCope rearrangementCombinatorial chemistryStereochemistryMedicinal chemistryOrganic chemistryOceanographyGeologyCyclopropane Reaction MechanismsCatalytic C–H Functionalization MethodsCatalytic Alkyne Reactions