Asymmetric Construction of Functionalized Cyclopenta[]pyrrolines via Cascade Aza-Piancatelli/Hydroamination Reactions.

A chiral Brønsted acid/Pd that cooperatively catalyzed the asymmetric cascade aza-Piancatelli rearrangement/hydroamination of readily accessible alkynyl-functionalized tertiary furylcarbinols with anilines has been developed. This protocol provides expedient access to a variety of densely functionalized cyclopenta[]pyrroline derivatives in high yields with excellent enantioselectivities.

Remote Radical Azidation of Unactivated C(sp)-H Bonds in Sulfamoyl Azides.

An efficient method for remote radical C(sp)-H azidation at unactivated sites is described. C-H functionalization proceeds via intramolecular 1,5-hydrogen atom transfer to N-centered radicals that are generated via azido group transfer and/or fragmentation. The readily installed sulfamoyl azide serves as both an amidyl radical precursor and an azido source.

Ln(III)/Chiral Brønsted Acid Catalyzed Asymmetric Cascade Ring Opening/Aza-Piancatelli Rearrangement of D-A Cyclopropanes.

The first Lewis acid and chiral Brønsted acid cooperatively catalyzed asymmetric cascade ring opening/aza-Piancatelli rearrangement reaction of furyl-substituted donor-acceptor cyclopropanes is achieved, enabling the construction of functionalized aminocyclopentenones bearing α-quaternary carbon stereocenters in high yields with excellent enantio- and diastereoselectivities under remarkably low catalyst loading of 0.2-1.2 mol %.