Cycloaddition of (phenylsulfonyl)-1,2-propadienes with diazomethane. Novel rearrangement reactions of the resulting cycloadducts
摘要:
The cycloaddition reactions of several phenylsulfonyl-substituted allenes with diazomethane have been investigated. The major products formed were identified as 3-(phenylsulfonyl)-4-methylene-2-pyrazolines. These pyrazolines engage in a variety of mechanistically interesting transformations, ranging from base-catalyzed rearrangements to addition of Grignard reagents. The dipolar cycloadduct derived from the reaction of diazomethane with 3-(phenylsulfonyl)-1,2-butadiene undergoes a 1,3-phenylsulfonyl shift upon irradiation to give 3-methyl-4-[(phenylsulfonyl)methyl]pyrazole. The cycloadduct derived from there action of 2,3-bis(phenylsulfonyl)-1-propene with diazomethane readily loses nitrogen upon photolysis to give 1-[(phenylsulfonyl)methyl]-1-(phenylsulfonyl)cyclopropane. This cyclopropane affords a variety of novel rearranged structures when treated with several different bases. The products obtained can be rationalized in terms of a base-catalyzed rearrangement of the above cyclopropane to a-methyl(phenylsulfonyl)allene which reacts further with the particular base used to produce the observed products.
The [2,3]-sigmatropic rearrangement of propargyl benzenesulphinates to allenyl phenyl sulphones
作者:S. Braverman、H. Mechoulam
DOI:10.1016/s0040-4020(01)97078-4
日期:1974.1
undergo thermalrearrangement in high yields to sulphones, accompanied by a simultaneous acetylene-allene isomerization. The allenic sulphones produced by the rearrangement of the α-monosubstituted propargyl esters underwent further rearrangement under the reaction conditions, to γ-substituted propargyl phenyl sulphones, by way of a base-catalyzed [1,3] - prototropic shift. A kinetic study of the rearrangement
Observation of the First Heck-Type Cross-Coupling Reaction of Allenes with Aryl Halides. Synthesis of Polysubstituted 1,2-Allenyl Sulfones
作者:Chunling Fu、Shengming Ma
DOI:10.1021/ol050301j
日期:2005.4.14
[reaction: see text] The Heck-type allenylation of aryl halides with allenes has been observed for the first time: The regioselectivity of intermolecular carbopalladation of 1,2-allenyl sulfones affording vinylic Pd intermediates is completely opposite to what was reported in the literature.
Highly Regio- and Stereoselective Oxidative Hydroacetoxylation of 1,2-Allenylic Sulfoxides via a Different Mechanism
作者:Chao Zhou、Zhao Fang、Chunling Fu、Shengming Ma
DOI:10.1021/jo802755k
日期:2009.4.3
A highlyregio- and stereoselective oxidative hydroacetoxylation of 1,2-allenylicsulfoxides affording 1-sulfonyl-1-alken-3-yl acetates in moderate to good yields was developed. Through the X-ray diffraction study, it was observed that the reaction may proceed via a 5-membered cyclic intermediate and the −OAc attacks the chiral carbon atom, which is different from what was observed in our previous
Synthesis of 1,4-Enamino Ketones by [3,3]-Rearrangements of Dialkenylhydroxylamines
作者:Wiktoria H. Pecak、Jongwoo Son、Amy J. Burnstine、Laura L. Anderson
DOI:10.1021/ol501230e
日期:2014.7.3
4-enamino ketones has been achieved through the [3,3]-rearrangement of dialkenylhydroxylamines generated from the addition of N-alkenylnitrones to electron-deficient allenes. The mild conditions required for this reaction, and the simultaneous installation of a fluorenyl imine N-protecting group as a consequence of the rearrangement, avoid spontaneous cyclization of the 1,4-enamino ketones to form the
Direct synthesis of highly substituted thiophenes through copper(i)-catalyzed tandem reactions of alkylidenethiiranes with terminal alkynes
作者:Yiping Zhang、Ming Bian、Weijun Yao、Jianming Gu、Cheng Ma
DOI:10.1039/b909284f
日期:——
A novel copper(i)-catalyzed tandem addition/cycloisomerization reaction of 1-phenylsulfonylalkylidenethiiranes with terminal alkynes for the convergent assembly of 2-(alpha-phenylsulfonylalkyl)-thiophenes is reported, which could directly assemble various functional groups incorporated into the thiophene ring.