Rhodium-Catalyzed Asymmetric -C5 Allylation of Indazoles with Dienyl Allylic Alcohols.

The development of site-selective and regio- and enantioselective reactions of substrates with multiple active sites is an important topic and remains a substantial challenge in synthetic chemistry. Here, we describe a rhodium-catalyzed asymmetric -C5 allylation of indazoles with dienyl allylic alcohols under mild conditions. In the presence of a Rh/(P/olefin) catalyst and formic acid, chiral -C5 allylic indazoles were formed in good yields with excellent enantioselectivities (up to 97% ee). The mechanism proceeds through an elusive intermediate , which represents a challenging task on asymmetric allylic substitution (AAS) of dienyl substrates.