Rhodium-Catalyzed Asymmetric Hydroselenation of 1-Alkynylindoles for Atroposelective Synthesis of Vinyl Selenoethers
Yulong Kang, Fen Wang, Xingwei Li
Abstract
Catalytic asymmetric hydrofunctionalization of π-bonds has been extensively studied, but the asymmetric hydrofunctionalization of alkynes that affords atropoisometric products remains heavily underexplored. We herein report [Rh(COD)OAc] 2 /Mg(NTf 2 ) 2 -catayzed highly atroposelective hydroselenation of two classes of 1-alkynylindoles using selenophenols, where the Mg(II) salt both activates the Rh catalyst and provides a key NTf 2 anion essential for the catalytic activity and enantioselectivity, affording C–N axially chiral trisubstituted olefins that bear a relatively low racemization barrier (Δ G ‡ ∼ 27 kcal/mol). The catalytic system features high activity, mild reaction conditions, good functional group tolerance, and high regio-, ( E )-, and enantioselectivity. The selenoether moiety in the product framework can be readily functionalized to give synthetically useful products.