Asymmetric Catalytic Aerobic Oxidative Radical Addition/Hydroxylation/1,4-Aryl Migration Reaction of Olefins

Abstract

The radical aryl migration reactions provide a synthetic methodology capable of constructing interesting building blocks that are not readily accessible via traditional processes. However, efficient methods to perform radical 1,4-aryl migration in stereoselective manner are fully challenging, and particularly functionalized starting materials and harsh reaction conditions are usually required, much less asymmetric catalytic versions. Here, we reported the breakthrough in diastereo-and enantioselective catalytic aerobic oxidative radical addition/hydroxylation/1,4-aryl migration processes from bisaryl-substituted ethenes and indanone derivatives. We disclosed that the combination of CuI/O 2 oxidative system and chiral Lewis acid-involved asymmetric catalysis synergistically enabled the direct generation of optically enriched 3-arylated indanone derivatives under mild reaction conditions. The aerobic oxidative addition provided a straightforward and in situ generation of diaryl alcohol and distal radical for 1,4-aryl migration. An easily available chiral magnesium complex catalyst could relay chiral information in radical addition and 1,4-aryl migration with high diastereo-and enantioselectivity.

Asymmetric magnesium catalysis for important chiral scaffold synthesis

“…20 A chiral N , N ′-dioxide/Mg( ii ) complex was employed as an efficient catalyst. 21 Wide ranges of glycine pyrazoleamides and allyl bromides were selected for extending the reaction scope, while moderate to good yields and high ee values could be obtained under the classic catalytic system. A possible catalytic cycle was proposed for the reaction, initiated by the generation of corresponding ammonium salt 6-I , which was next activated after bidentate coordination to the magnesium centre, and the deprotonation process with the added base would afford the metal-bonded ammonium ylide 6-II .…”