Synergistic Catalysis of Ionic Brønsted Acid and Photosensitizer for a Redox Neutral Asymmetric α-Coupling of N-Arylaminomethanes with Aldimines
摘要:
A redox neutral, highly enantioselective coupling between N-arylaminomethanes and N-sulfonyl aldimines was developed by harnessing the efficient catalysis of P-spiro chiral arylaminophosphonium barfate and a transition-metal photosensitizer under visible light irradiation. This mode of synergistic catalysis provides a powerful strategy for controlling the bond-forming processes of reactive radical intermediates.
The Generation of Difluoroketenimine and Its Application in the Synthesis of α,α‐Difluoro‐β‐amino Amides
作者:Rui Zhang、Zhikun Zhang、Qi Zhou、Lefei Yu、Jianbo Wang
DOI:10.1002/anie.201901591
日期:2019.4.16
Fluorine‐containing β‐amino acids and their derivatives have attracted significant attention due to their importance in life sciences. Herein the previously unknown difluoroketenimine, the analogue of the elusive difluoroketene, has been generated by the reaction of difluorocarbene and isocyanide, which further undergoes [2+2] cycloaddition with imine. The three‐component reaction affords α,α‐difluoro‐β‐amino amides
Cross-Selective Aza-Pinacol Coupling via Atom Transfer Catalysis
作者:Sean M. Rafferty、Joy E. Rutherford、Lumin Zhang、Lu Wang、David A. Nagib
DOI:10.1021/jacs.1c00886
日期:2021.4.21
homodimerization by a classical reductive approach. In this first example of reductive, ketyl coupling by atom transfer catalysis, Zn serves as a terminal reductant to facilitate Mn catalyst turnover. This new strategy also enables ketyl radical couplings to alkenes, alkynes, aldehydes, propellanes, and chiral imines.
Mild, Redox-Neutral Alkylation of Imines Enabled by an Organic Photocatalyst
作者:Niki R. Patel、Christopher B. Kelly、Allison P. Siegenfeld、Gary A. Molander
DOI:10.1021/acscatal.6b03665
日期:2017.3.3
operationally simple, mild, redox-neutral method for the photoredox alkylation of imines is reported. Utilizing an inexpensive organic photoredox catalyst, alkyl radicals are readily generated from the single-electron oxidation of ammonium alkyl bis(catecholato)silicates and are subsequently engaged in a C–C bond-forming reaction with imines. The process is highly selective, metal-free, and does not require
Independence from the Sequence of Single-Electron Transfer of Photoredox Process in Redox-Neutral Asymmetric Bond-Forming Reaction
作者:Tomohito Kizu、Daisuke Uraguchi、Takashi Ooi
DOI:10.1021/acs.joc.6b00445
日期:2016.8.19
chiral (arylamino)phosphonium tetrakis[3,5-bis(trifluoromethyl)phenyl]borate under visible light irradiation. This achievement clearly demonstrates the insensitivity of this redox-neutral asymmetric reaction to the sequence of the key redox events involved in the synergistic catalysis.
Tunable stereoselective alkene synthesis by treatment of activated imines with nonstabilized phosphonium ylides
作者:De-Jun Dong、Yuan Li、Jie-Qi Wang、Shi-Kai Tian
DOI:10.1039/c0cc04739b
日期:——
A broad range of readily accessible N-sulfonyl imines undergo olefination reaction with nonstabilized phosphoniumylides under mild conditions to afford an array of both Z- and E-isomers of 1,2-disubstituted alkenes, allylic alcohols, and allylic amines in good yields and with greater than 99 : 1 stereoselectivity.