Copper-Catalyzed Enantioselective 1,2-Allylation of Azadienes with Allylboronates

Abstract

Catalytic asymmetric 1,2-allylation of auronederived azadienes is very difficult to achieve due to the driving force for aromatization and the greater steric hindrance of 1,2addition compared with 1,4-addition. By taking advantage of the ability of nitrogen ligated metal complexes, we successfully demonstrated the first example of copper-catalyzed 1,2-allylation of azadienes with allylboronates for the highly enantioselective synthesis of homoallylic amines. Meanwhile, the enantioenriched 1,4-addition products could also be obtained through a subsequent 3,3-sigmatropic rearrangement of the 1,2-addition products. Extensive DFT calculations were carried out to elucidate the origins of high regioselectivity (1,2-vs 1,4-) and enantioselectivity.

Scaffold-Hopping Strategies in Aurone Optimization: A Comprehensive Review of Synthetic Procedures and Biological Activities of Nitrogen and Sulfur Analogues

“…Method IB, instead, involves a lithium diisopropylamide (LDA)-mediated in situ anionic cyclization of N,N-diethyl-2-(methylthio)benzamide 43 , which is achieved by the directed ortho-metalation of the corresponding benzamide followed by quenching with dimethyl disulfide [ 56 , 57 , 58 ]. Intermediate 44 undergoes aldol condensation with aromatic aldehydes using piperidine/NaOH/basic aluminum oxide under basic catalyst conditions or acetic acid and sodium acetate under acidic catalysis to give the title thioaurone scaffold [ 54 , 55 , 56 , 57 , 58 , 59 , 60 ].…”