Evidence and isolation of tetrahedral intermediates formed upon the addition of lithium carbenoids to Weinreb amides and N-acylpyrroles
作者:Laura Castoldi、Wolfgang Holzer、Thierry Langer、Vittorio Pace
DOI:10.1039/c7cc05215d
日期:——
The tetrahedralintermediates generated upon the addition of halolithium carbenoids (LiCH2X and LiCHXY) to Weinreb amides have been intercepted and fully characterized as O-TMS heminals. The commercially available N-trimethylsilyl imidazole is the ideal trapping agent whose employment, combined with a straightforward neutral Alox chromatographic purification, enables the isolation of such labile species
Catalytic Enantioselective Amination of Enolsilanes Using <i>C</i><i><sub>2</sub></i>-Symmetric Copper(II) Complexes as Chiral Lewis Acids
作者:David A. Evans、Douglas S. Johnson
DOI:10.1021/ol990113r
日期:1999.8.1
[formula: see text] [Cu(S,S)-t-Bu-box](OTf)2 (1) catalyzes the enantioselective amination of enolsilanes with azodicarboxylate derivatives. Isomerically pure enolsilanes of aryl ketones, acylpyrroles, and thioesters added to the azo-imide in greater than 95% ee. The use of an alcohol additive was critical to achieving catalyst turnover.
Samarium-mediated intramolecular cross-couplings of an α,β-unsaturated N-acylpyrrole
作者:Katherine R. Law、Christopher S.P. McErlean
DOI:10.1016/j.tetlet.2016.06.010
日期:2016.7
The first example of an α,β-unsaturated N-acylpyrrole undergoing a SmI2-mediated cyclization is reported. In contrast to other unsaturated units, the intermediate samarium enolate readily engages in aldol-type reactions, necessitating careful control of the reaction conditions.
Ni-catalyzed direct alcoholysis of N-acylpyrrole-type tertiary amides under mild conditions
作者:Hang Chen、Dong-Huang Chen、Pei-Qiang Huang
DOI:10.1007/s11426-019-9665-5
日期:2020.3
Abstract N-Acylpyrrole-type amides are a class of versatile building blocks in asymmetric synthesis. We report that by employing Ni(COD)2/2,2′-bipyridine (5 mol%) catalytic system, the direct, catalytic alcoholysis of N-acylpyrrole-type aromatic and aliphatic amides with both primary and secondary alcohols can be achieved efficiently under very mild conditions (rt, 1 h) even at gram scale. By increasing
Nickel-Catalyzed Reduction of Secondary and Tertiary Amides
作者:Bryan J. Simmons、Marie Hoffmann、Jaeyeon Hwang、Moritz K. Jackl、Neil K. Garg
DOI:10.1021/acs.orglett.7b00683
日期:2017.4.7
The nickel-catalyzed reduction of secondary and tertiary amides to give amine products is reported. The transformation is tolerant of extensive variation with respect to the amide substrate, proceeds in the presence of esters and epimerizable stereocenters, and can be used to achieve the reduction of lactams. Moreover, this methodology provides a simple tactic for accessing medicinally relevant α-deuterated