Rhodium-Catalyzed Selective C(sp2)-H Activation/Annulation of tert-Butyl Benzoyloxycarbamates with 1,3-Diynes: A One Step Access to Alkynylated Isocoumarins and Bis-Isocoumarins

We report here a Rh(III) catalyzed regio-and stereoselective synthesis of alkynylated and bis-isocoumarin from 1,3-dialkyne. Exclusive one-pot formation of 3,3-bis-isocoumarin isomers has been achieved by eliminating several other possibilities. This is the first example of transition metal catalyzed synthesis of alkynylated and bis-isocoumarin scaffolds. The protocol is compatible with a wide range of functional groups affording good to excellent yields. Several mechanistic investigations, including deuterium labeling experiments and kinetic isotope effect studies, have been carried out.

Automated summary

In this study, a Rh(III) catalyzed synthesis of alkynylated and bis-isocoumarin compounds from 1,3-dialkyne was reported. Exclusive one-pot formation of 3,3-bis-isocoumarin isomers was achieved, eliminating several other possibilities. This is the first example of transition metal catalyzed synthesis of alkynylated and bis-isocoumarin scaffolds, and the protocol is compatible with a wide range of functional groups.