Simultaneous Synthesis of Both Rings of Chromenes via a Benzannulation/<i>o</i>-Quinone Methide Formation/Electrocyclization Cascade
作者:Nilanjana Majumdar、Keith A. Korthals、William D. Wulff
DOI:10.1021/ja210655g
日期:2012.1.18
A new route to the chromene ring system has been developed which involves the reaction of an α,β-unsaturated Fischer carbenecomplex of chromium with a propargyl ether bearing an alkenyl group on the propargylic carbon. This transformation involves a cascade of reactions that begins with a benzannulation reaction and is followed by the formation of an o-quinone methide, and finally results in the emergence
开发了一种色烯环体系的新路线,该路线涉及铬的α,β-不饱和费歇尔卡宾络合物与在炔丙碳上带有烯基的炔丙醚的反应。这种转化涉及一系列反应,从苯并环化反应开始,然后形成邻醌甲基化物,最后在电环化时产生色烯。通过使用芳基卡宾络合物,该反应被扩展以提供通路。这是色烯的首次合成,其中色烯系统的两个环均在一步中生成,并在 lapachenole 和维生素 E 的合成中得到突出体现。
Synthesis of Naphthalenes through Three-Component Coupling of Alkynes, Fischer Carbene Complexes, and Benzaldehyde Hydrazones via Isoindole Intermediates
作者:Shaofeng Duan、Dilip K. Sinha-Mahapatra, and、James W. Herndon
DOI:10.1021/ol800242n
日期:2008.4.1
The synthesis of naphthalene derivatives through three-component coupling of 2-alkynylbenzaldehyde hydrazones with carbene complexes and electron-deficient alkynes has been examined. The reaction involves formation of an isoindole derivative, followed by intramolecular Diels-Alder reaction, followed by nitrene extrusion. The reaction was highly regioselective using unsymmetrical alkynes.
Simultaneous and Stereoselective Construction of Planar and Axial Centers of Chirality
作者:Louis Fogel、Richard P. Hsung、William D. Wulff、Roger D. Sommer、Arnold L. Rheingold
DOI:10.1021/ja010091f
日期:2001.6.1
all of these alkynes, the reaction products could be completely isomerized to the anti isomer by performing the reaction at 120 °C except for the smaller ortho methoxyl complex which only required 50 °C for complete conversion. This includes the very hindered tertbutyl complex3i which was formed as a slightly preferred kinetic product having the syn stereochemistry which was determined by X-ray diffraction
The preparation of imidazolidinone and oxazolidinone chelated carbene complexes
作者:Timothy S Powers、William D Wulff、John Quinn、Yan Shi、Weiqin Jiang、Richard Hsung、Mark Parisi、Annette Rahm、Xiao Wu Jiang、Glenn P.A Yap、Arnold L Rheingold
DOI:10.1016/s0022-328x(00)00734-8
日期:2001.1
these complexes. The imidazolidinone complexes are best prepared by adding an imidazolidinone or lithiated imidazolidinone to a methoxy carbenecomplex or to an in-situ generated acetoxy carbenecomplex. α,β-Unsaturated imidazolidinone complexes are prepared by aldol condensations of alkyl imidazolidinone complexes or by alkylaltion of these complexes with bromomethyl methyl ether and then elimination
(CO)4 M = CC(R 1)NCO(CHR 2 CHR 3 X)类型的几种内部螯合的咪唑啉酮和恶唑烷酮费希尔卡宾配合物的合成据报道,其中M =铬,钨;[R 1 =甲基,乙基,异丙基,苯基,反式-丙烯基,异丙烯基,异丁烯基,环己烯基和1-丙炔基; R 2= H,Ph,Bn,Me,Cy;R 3= H,我,Ph;X = O,NMe。四种不同的方法用于合成这些配合物。最好将咪唑烷酮或锂化的咪唑烷酮加入甲氧基卡宾配合物或原位生成的乙酰氧基卡宾配合物中来制备咪唑烷酮配合物。α,β-不饱和咪唑烷酮配合物是通过烷基咪唑烷酮配合物的羟醛缩合或通过将这些配合物与溴代甲基甲醚烷基化,然后除去甲醇而制备的。最佳的恶唑烷酮配合物是通过两步程序制备的,该过程包括向甲氧基或乙酰氧基配合物中添加β-氨基醇,然后用光气将所得的氨基卡宾配合物封闭到恶唑烷酮配合物中。