Organocatalyzed Enantioselective [2 + 2] Cycloaddition of ,-Cyclic Ketimines and Allenoates.

We report a novel enantioselective and regioselective [2 + 2] cycloaddition of allenoate and ,-cyclic ketimine catalyzed by a quinidine derivative. The methodology enables the synthesis of fused tricyclic azetidines with a quaternary stereogenic center exhibiting high enantioselectivities. The broad range of substrates demonstrates the generality of the protocol, and the resulting functional products can be easily converted to a variety of valuable synthons.

Mechanism and Selectivity of Copper-Catalyzed Bromination of Distal C(sp)-H Bonds.

Unactivated C(sp)-H bonds are the most challenging substrate class for transition metal-catalyzed C-H halogenation. Recently, the Yu group [Liu, T.; Myers, M.

Stereospecific [3+2] Cycloaddition of Chiral Arylallenes with C,N-Cyclic Azomethine Imines.

A novel α,β-regioselective [3+2] cycloaddition reaction of arylallene with C,N-cyclic azomethine imine is reported. The axial-to-central chirality transfer phenomenon has been disclosed with chiral allenes in the reaction. The wide substrate scope, including different functional groups and natural products, reveals the generality of the methodology.

Correction: Mechanistic details of the cobalt-mediated dehydrogenative dimerization of aminoquinoline-directed benzamides.

[This corrects the article DOI: 10.1039/D0SC02066D.].