Rhodium-Catalyzed Asymmetric Hydroselenation of 1‑Alkynylindoles\nfor Atroposelective Synthesis of Vinyl Selenoethers

Catalytic\nasymmetric hydrofunctionalization of π-bonds has\nbeen extensively studied, but the asymmetric hydrofunctionalization\nof alkynes that affords atropoisometric products remains heavily underexplored.\nWe herein report [Rh(COD)OAc]<sub>2</sub>/Mg(NTf<sub>2</sub>)<sub>2</sub>-catayzed highly atroposelective hydroselenation of two classes\nof 1-alkynylindoles using selenophenols, where the Mg(II) salt both\nactivates the Rh catalyst and provides a key NTf<sub>2</sub> anion\nessential for the catalytic activity and enantioselectivity, affording\nC–N axially chiral trisubstituted olefins that bear a relatively\nlow racemization barrier (Δ<i>G</i><sup>‡</sup> ∼ 27 kcal/mol). The catalytic system features high activity,\nmild reaction conditions, good functional group tolerance, and high\nregio-, (<i>E</i>)-, and enantioselectivity. The selenoether\nmoiety in the product framework can be readily functionalized to give\nsynthetically useful products.