Cobalt-catalyzed cyclization with the introduction of cyano, acyl and aminoalkyl groups
作者:Hiroto Hori、Shigeru Arai、Atsushi Nishida
DOI:10.1039/c9ob00637k
日期:——
An efficient synthesis of carbo- and heterocycles using CC, CO and CN bonds undercobaltcatalysis is described. The substituents on olefins are key for controlling the regio- and chemoselectivity in the initial hydrogen atom transfer step and quaternary carbons are efficiently constructed under mild conditions. Cyclopropane cleavage and tandem cyclization give highly functionalized bicyclic skeletons
A Construction of α-Alkenyl Lactones via Reduction Radical Cascade Reaction of Allyl Alcohols and Acetylenic Acids
作者:Hua Zhang、Guo-Min Zhang、Shuai He、Zhi-Chuan Shi、Xiao-Mei Zhang、Ji-Yu Wang
DOI:10.1021/acs.orglett.0c02973
日期:2020.11.6
An iron-catalyzed cascade reaction of radical reduction of allyl alcohols and acetylenic acids to construct polysubstituted α-alkenyl lactones has been developed. In this paper, various allyl alcohols can form allyl ester intermediates and are further transformed into alkyl radicals, which form products through intramolecular reflex-Michael addition. In addition, this method can be used to prepare
we describe a simple and practical protocol for the reduction of carboxylicacidsvia the in situ formation of hydroxybenzotriazole esters followed by reaction with sodiumborohydride to give the corresponding alcohols. The reaction proceeds with excellent yields in the presence of water. alcohol - carboxylicacids - reduction - benzotriazole esters - carbodiimide
Mizoroki–Heck Cyclizations of Amide Derivatives for the Introduction of Quaternary Centers
作者:Jose M. Medina、Jesus Moreno、Sophie Racine、Shuaijing Du、Neil K. Garg
DOI:10.1002/anie.201703174
日期:2017.6
report non-decarbonylative Mizoroki–Heck reactions of amide derivatives. The transformation relies on the use of nickel catalysis and proceeds using sterically hindered tri- and tetrasubstituted olefins to give products containing quaternary centers. The resulting polycyclic or spirocyclic products can be obtained in good yields. Moreover, a diastereoselective variant of this method gives access to an
Highly Enantioselective Copper-Catalyzed Alkylation of β-Ketoesters and Subsequent Cyclization to Spirolactones/Bi-spirolactones
作者:Qing-Hai Deng、Hubert Wadepohl、Lutz H. Gade
DOI:10.1021/ja211859w
日期:2012.2.15
Cu-catalyzed enantioselective alkylation of β-ketoesters using alcohols for in situ preparation of alkylating reagents is reported. A number of functionalized β-ketoesters containing a quaternary carbon stereocenter are obtained with up to 99% ee. The alkylation products derived from 2-substituted allylic alcohols or their corresponding iodides can then be converted to spirolactones, bi-spirolactones
报道了使用醇对 β-酮酯进行 Cu 催化的对映选择性烷基化,用于原位制备烷基化试剂。获得了许多含有季碳立体中心的官能化 β-酮酯,ee 高达 99%。然后可以将衍生自 2-取代烯丙醇或其相应碘化物的烷基化产物转化为螺内酯、双螺内酯和相关的手性目标产物。