Rhodium-Catalyzed Enantioselective Oxidative [3+2] Annulation of Arenes and Azabicyclic Olefins through Twofold C-H Activation.

C-H bond activation is mostly limited to ortho selectivity. Activation of both ortho and meta C-H bonds constitutes a particularly important strategy for annulation, but has rarely been studied in enantioselective systems. Reported herein is rhodium(III)-catalyzed asymmetric [3+2] transannulation of arenes with 7-azabenzonorbornadienes. Two distinct classes of arenes have been identified as substrates, and the coupling proceeded with high enantioselectivity and excellent diastereoselectivity through sequential activation of ortho and meta C-H bonds.

trans-Cyclooctenes as Halolactonization Catalysts.

The strained olefins in trans-cyclooctenes serve as efficient catalysts for halolactonizations, including bromolactonizations and iodolactonizations. The trans-cyclooctene framework is essential for excellent catalytic performance, and the substituents also play important roles in determining efficiency. These results are the first demonstration of catalysis by a trans-cyclooctene.

Unprecedented Dearomatized Spirocyclopropane in a Sequential Rhodium(III)-Catalyzed C-H Activation and Rearrangement Reaction.

An unprecedented dearomatized spirocyclopropane intermediate was discovered in a sequential Cp*RhIII -catalyzed C-H activation and Wagner-Meerwein-type rearrangement reaction. How the oxidative O-N bond is cleaved and the role of HOAc were uncovered in this study. Furthermore, a Cp*RhIII -catalyzed dearomatization reaction of N-(naphthalen-1-yloxy)acetamide with strained olefins was developed, affording a variety of spirocyclopropanes.