N-H ketoimines 3a-3v are readily prepared in high yield via organometallic addition to nitrites and isolated as corresponding bench-stable hydrochloride salts. Homogeneous asymmetric hydrogenation of unprotected N-H ketoimines 3a-3v using Ir-(S,S)-f binaphane as catalyst provides chiral amines 4a-4v in 90-95% yield with enantioselectivities up to 95% ee.
Synthesis of Sterically Hindered Primary Amines by Concurrent Tandem Photoredox Catalysis
作者:Michael C. Nicastri、Dan Lehnherr、Yu-hong Lam、Daniel A. DiRocco、Tomislav Rovis
DOI:10.1021/jacs.9b10871
日期:2020.1.15
methodologies exist for amine synthesis, but the direct synthesis of primary amines with a fully substituted α carbon center is an underdeveloped area. We report a method which utilizes photoredox catalysis to couple readily available O-benzoyl oximes with cyanoarenes to synthesize primary amines with fully substituted α-carbons. We also demonstrate that this method enables the synthesis of amines with α-trifluoromethyl
Electrochemical Synthesis of Hindered Primary and Secondary Amines via Proton-Coupled Electron Transfer
作者:Dan Lehnherr、Yu-hong Lam、Michael C. Nicastri、Jinchu Liu、Justin A. Newman、Erik L. Regalado、Daniel A. DiRocco、Tomislav Rovis
DOI:10.1021/jacs.9b10870
日期:2020.1.8
Accessing hindered amines, particularly primary amines α to a fully substituted carbon center, is synthetically challenging. We report an electrochemical method to access such hindered amines starting from benchtop-stable iminium salts and cyanoheteroarenes. A wide variety of substituted heterocycles (pyridine, pyrimidine, pyrazine, purine, azaindole) can be utilized in the cross-coupling reaction