Me<sub>2</sub>Zn-Mediated Addition of Acetylenes to Aldehydes and Ketones
作者:Pier Giorgio Cozzi、Jens Rudolph、Carsten Bolm、Per-Ola Norrby、Claudia Tomasini
DOI:10.1021/jo050115r
日期:2005.7.1
Contrary to expectations, commercially available 2 M Me2Zn in toluene is able to promote the addition of phenylacetylene to aldehydes and ketones. This reactivity is determined by a new, unprecedented mechanism, which involves activation of the zinc reagent via coordination with carbonyl substrates that behave “ligand like”. Broad scope, high tolerance to functional groups, and a simple procedure make
与预期相反,在甲苯中可商购的2 M Me 2 Zn能够促进将苯乙炔添加到醛和酮中。这种反应性是由一种新的,前所未有的机制决定的,该机制涉及通过与表现为“配体样”的羰基底物的配位来激活锌试剂。宽泛的范围,对官能团的高度耐受性以及简单的操作步骤使这种新方法对于合成化学家而言非常有趣。
Electrochemical Alkynyl/Alkenyl Migration for the Radical Difunctionalization of Alkenes
作者:Yongyuan Gao、Haibo Mei、Jianlin Han、Yi Pan
DOI:10.1002/chem.201804157
日期:2018.11.22
An efficient electrochemical 1,2‐sulfonylation/alkynylation of alkenes via radical 1,4‐alkynyl migration of alkynyl‐substituted tertiary alcohols is described, which used sodium sulfinates as sulfonyl sources affording the corresponding α‐sulfonyl‐β‐alkynylated products in moderate to excellent yields. This electrochemical reaction proceeds smoothly without the use of any metal catalyst, additive and
accessible tertiary propargyl vinyl ethers as substrates and imidazole as a catalyst to form up to two new rings, three new C−C bonds, six stereogenic centers and one transannular oxo‐bridge. The manifold is efficient, scalable and instrumentally simple to perform and entails a propargyl Claisen rearrangement–[1,3]H shift, an oxa‐6π‐electrocyclization, and an intramolecularDiels–Alderreaction.
Oxidative cyclization of tertiary pentenol derivatives forming 2,5,5-trisubstituted THF rings and the total synthesis of cyclocapitelline
作者:Geoffrey A. Phillips、Cory Palmer、Andrew C. Stevens、Mathew L. Piotrowski、Daryl S.R. Dekruyf、Brian L. Pagenkopf
DOI:10.1016/j.tetlet.2015.09.064
日期:2015.10
The synthesis of 2,5,5-trisubstituted tetrahydrofuran rings was accomplished via the Mukaiyama aerobic oxidativecyclization of tertiary 5-pentenols employing the Co(nmp)2 catalyst. A variety of THFs were formed in moderate to good yield and diastereoselectivity. The method developed herein was successfully applied to an enantioselective total synthesis of cyclocapitelline.
Visible-Light-Driven Selective Alkenyl C–P Bond Cleavage of Allenylphosphine Oxides
作者:Kai Wei、Kai Luo、Fang Liu、Lei Wu、Li-Zhu Wu
DOI:10.1021/acs.orglett.9b00071
日期:2019.4.5
irradiation, was developed. This novel protocol involves a highly regioselective radical pathway initiated by singlet oxygen, affording diverse alkynyl phosphinates with good-to-excellent yields. Mechanistic studies and density functional theory calculations suggested an intramolecular process involving phosphorus migration, instead of phosphorus radical formation, at the early stage of the reaction