In Situ Generation of Quinolinium Ylides from Diazo Compounds: Copper-Catalyzed Synthesis of Indolizine
作者:Rongxiang Chen、Yanwei Zhao、Hongmei Sun、Ying Shao、Yudong Xu、Meihua Ma、Liang Ma、Xiaobing Wan
DOI:10.1021/acs.joc.7b01042
日期:2017.9.15
The Cu-catalyzedthree-component reaction between quinolines, diazo compounds, and alkenes has been established for direct construction of indolizine derivatives via quinolinium ylides. This methodology is distinguished by the use of a commercially inexpensive catalyst and readily available starting materials, wide substrate scope, and operational simplicity.
Regio- and Stereoselective Copper(II)-Catalyzed Hydrosilylation of Activated Allenes in Water: Access to Vinylsilanes
作者:Srinath Pashikanti、Joseph A. Calderone、Matthew K. Nguyen、Christopher D. Sibley、Webster L. Santos
DOI:10.1021/acs.orglett.6b00981
日期:2016.5.20
By using catalytic amounts of copper(II), 4-picoline, and dimethylphenylsilylpinacol borane, a series of allenoates were silylated on the β carbon in good to excellent yields and high (E)-selectivity. The mild and efficient silylation method is conducted in water under atmospheric conditions to afford vinylsilanes.
Microwave-Assisted Intramolecular [2 + 2] Allenic Cycloaddition Reaction for the Rapid Assembly of Bicyclo[4.2.0]octa-1,6-dienes and Bicyclo[5.2.0]nona-1,7-dienes
作者:Kay M. Brummond、Daitao Chen
DOI:10.1021/ol051115g
日期:2005.8.1
[2 + 2] cycloaddition reaction. This cycloaddition provides an efficient route to bicyclomethylenecyclobutenes. The reaction occurs with complete regioselectivity for the distal double bond of the allene for the selective formation of a variety of hetero- and carbocyclic substrates. Bicyclo[4.2.0]octadienes and bicyclo[5.2.0]nonadienes have been prepared in high yield. [reaction: see text]
Rhodium(II)-catalyzed cyclization of 2-alkynyl 2-diazo-3-oxobutanoates as a method for synthesizing substituted furans
作者:Albert Padwa、Frederick R. Kinder
DOI:10.1021/jo00053a009
日期:1993.1
A series of 2-alkynyl 2-diazo-3-oxobutanoates, when treated with a catalytic quantity of rhodium(II) acetate, were found to produce furo[3,4-c]furans in good yield. The reaction proceeds by addition of a rhodium-stabilized carbenoid onto the acetylenic pi-bond to give a vinyl carbenoid which subsequently cyclizes onto the neighboring carbonyl group to produce the furan ring. In a similar manner, indeno[1,2-c]furans were produced from 2-butynyl 2-diazoarylacetates. Compounds substituted with methyl groups on the propargylic carbon atom cyclized at a slower rate. This rate diminution is attributed to the fact that the unsubstituted propargyl group can more easily achieve the required conformation for cyclization. C-H insertion was found to compete with furan formation when an alkyl group was attached to the keto functionality of the starting diazo acetoacetate. Diazo alkynyl sulfones undergo a novel oxygen transfer reaction when treated with rhodium(II) acetate at 80-degrees-C. The cyclized product is formed by sulfone oxygen attack onto the vinyl carbenoid producing a dipolar species which subsequently collapses to give the butenolide sulfoxide.