A convenient synthesis of N-benzyloxy-.BETA.-lactams via N-benzyloxyimines.
作者:Kiyoshi IKEDA、Kazuo ACHIWA、Minoru SEKIYA
DOI:10.1248/cpb.37.1179
日期:——
N-Benzyloxy-β-lactams were prepared from N-benzyloxyimines by reaction with ketene trimethylsilyl acetals in the presence of trimethylsilyl triflate followed by cyclization, or with lithium ester enolates in one step.
The first example of intermolecular carbon radicaladdition to unactivated aldoxime ethers in the presence of BF3·OEt2 has provided a new efficient carboncarbon bond-forming method for the synthesis of a variety of amines.
decomposition of the methanesulfonyl radical into the methyl radical and the subsequent transfer of an iodine atom or phenyl telluride group was used to develop a tin-freeradical acylation reaction (see scheme; V-40=1,1'-azobis(cyclohexane-1-carbonitrile). The key was finding reactionconditionsunder which the I or PhTe transfer is faster than the direct addition of the alkyl radical to the methanesulfonyl oxime
Iridium(I)-Catalyzed α-C(sp<sup>3</sup>)–H Alkylation of Saturated Azacycles
作者:Pritha Verma、Jeremy M. Richter、Nikita Chekshin、Jennifer X. Qiao、Jin-Quan Yu
DOI:10.1021/jacs.9b12320
日期:2020.3.18
development of methods for functionalization of the α-methylene C‒H bonds of these highly privileged building blocks is of great importance, especially in drug discovery. While much effort has been dedicated towards this goal of using a directed C‒H activation approach, the development of directing groups that are both general, as well as practical, remains a significant challenge. Herein, the design and
Chirality Transfer in Rhodium(I)-Catalyzed [3 + 2]-Cycloaddition of Vinyl Aziridines and Oxime Ethers: Atom-Economical Synthesis of Chiral Imidazolidines
A highly efficient and stereoselective synthesis of enantioenriched imidazolidines by rhodium-catalyzed intermolecular [3 + 2] cycloaddition reaction of chiral vinyl aziridines and oxime ethers has been successfully developed. Notably, both aldoximes and ketoximes are suitable substrates to afford the corresponding chiral imidazolidines in high yields with good stereoselectivity. This transformation