3]-sigmatropic rearrangementreaction of α-alkylidene pyrazolinones and propargyl sulfonium salts has been reported to construct homoallyl sulfur-containing pyrazolones with moderate to excellent yields. α-Alkylidene pyrazolinones function as N-nucleophilic agents distinguished from the reported C-addition reactions. Propargyl sulfonium salts were first involved in the [2,3]-sigmatropic rearrangement protocol
A novel divergent domino annulation reaction of prop-2-ynylsulfonium salts with sulfonyl-protected β-amino ketones has been developed, affording various epoxide-fused 2-methylenepyrrolidines and S-containing pyrroles in moderate to excellent yields. Prop-2-ynylsulfonium salts act as C2 synthons in the reactions providing a promising epoxide-fused skeleton in a single operation with readily accessible
Divergent Domino Reactions of Prop-2-ynylsulfonium Salts: Access to Sulfur-Containing Benzo-Fused Dioxabicyclo[3.3.1]nonanes and Dihydrofuro[2,3-<i>c</i>]chromenes
作者:Yiming Zhou、Yu Chen、You Huang
DOI:10.1021/acs.orglett.0c02025
日期:2020.8.7
domino annulation reactions between 2-hydroxy-2-methylchromene derivatives and prop-2-ynylsulfonium salts have been developed. Specifically, a sequential [4 + 2] and [4 + 2] annulation reaction occurred in 1,2-dichloroethane affording sulfur-containing benzo-fused dioxabicyclo[3.3.1]nonanes. In contrast, by changing the solvent to toluene, the reaction course switched to a [4 + 2] and [4 + 1] annulation
已经开发了2-羟基-2-甲基苯甲基衍生物和丙-2-炔基ulf盐之间的溶剂控制的发散性多米诺环化反应。具体地,在[1,2-二氯乙烷]中发生顺序的[4 + 2]和[4 + 2]环化反应,得到含硫的苯并稠合的二氧杂双环[3.3.1]壬烷。相反,通过将溶剂改变为甲苯,反应过程切换为[4 + 2]和[4 +1]环化反应,得到二氢呋喃[2,3- c ]二甲基苯。值得注意的是,丙-2-炔基salt盐首次以其γ-碳原子参与转化。
A Formal [3+2] Annulation of
<i>β</i>
‐Oxoamides and 3‐Alkyl‐ or 3‐Aryl‐Substituted Prop‐2‐Ynyl Sulfonium Salts: Substrate‐Controlled Chemoselective Synthesis of Substituted
<i>γ</i>
‐Lactams and Furans
A substrate‐controlled synthesis of substituted γ‐lactams and furans has been developed via a formal [3+2] annulation of β‐oxoamides and 3‐alkyl/arylprop‐2‐ynyl sulfonium salts in the presence of cesium carbonate in a chemoselective manner. This novel protocol features easily available starting materials, mild reaction conditions, simple execution, and good to excellent yields of products.
Synthesis of methylene cyclopropane-fused chromenes and dihydroquinolines by sequential [4 + 2]- and [1 + 2]-annulation
作者:Tianyu Lu、Xuange Zhang、Zhiwei Miao
DOI:10.1039/d0ob00389a
日期:——
A base promoted sequential [4 + 2]- and [1 + 2]-annulation of 2-hydroxychalcones or 2-tosylaminochalcones with prop-2-ynylsulfonium salts has been developed to give the corresponding methylene cyclopropane fused dihydroquinolines or chromenes in moderate to good yields. This transformation has advantage of wide substrate scope and functional group tolerance as well as excellent regioselectivity. Prop-2-ynylsulfonium