Enantioselective Hydroalkynylation of Non‐Polar Carbon‐Carbon Double Bonds: Iridium‐Catalyzed Asymmetric Addition Reaction of Terminal Alkyne CH Bonds to Substituted Norbornadienes

Abstract

AbstractThis update describes the enantioselective addition of the terminal alkynyl CH bond across a non‐polar CC double bond. Sterically congested substrates are often challenging in this type of reaction as these alkenyl substrates exhibit poor substrate‐metal center coordination, and thus poor stereo‐induction would result. The successful enantioselective hydroalkynylation of this type of system has sporadically been reported. We herein describe our progress for the example of vinyl‐substituted norbornadiene derivatives. With the aid of an iridium complex in combination with the chiral SYNPHOS ligand, the addition products could be obtained smoothly with excellent enantioselectivities (up to 99% ee). In particular, the first examples of an acetylenic CH bond adding across azanorbornadienes are also disclosed.magnified image