New Method for the Preparation of Alkoxycarbene Complexes of Chromium, Molybdenum, and Tungsten Using Sulfonium Salts
作者:Takako Nakamura、Haruo Matsuyama、Masahiko Iyoda
DOI:10.1246/cl.1994.1537
日期:1994.8
Alkylation of tetramethylammonium acylate complexes of chromium, molybdenum, and tungsten with alkyldiphenylsulfonium salts readily proceeds under mild conditions to afford alkoxycarbene complexes containing a variety of functional groups in good yields.
Reactions of Complex Ligands, LXX. An Intramolecular Alkyne Insertion/Carbonylation/Cyclization Sequence of Chromium Aminocarbene Complexes: A Novel Access to Indole and Indenoindole Skeletons
作者:Thomas Leese、Karl Heinz Dötz
DOI:10.1002/cber.19961290606
日期:1996.6
2-Alkynylanilinocarbene chromium complexes 1–7 bearing a rigid arene C2 spacer between the aminocarbene and alkyne units were prepared from pentacarbonyl(aroyl)chromates(–I), acetyl bromide, and 2-alkynylanilines. They undergo intramolecular cyclization the course of which depends on the substitution pattern at the alkyne terminus. A tandem alkyne insertion into the metal–carbene bond/carbonylation
由五羰基(芳酰基)铬酸盐(-I),乙酰溴和2-炔基苯胺制备在氨基卡宾和炔烃单元之间带有刚性芳烃C 2间隔基的2-炔基丙二烯铬配合物1-7。它们经历分子内环化,其过程取决于炔烃末端的取代方式。一种串列炔插入得到的Cr(CO)的金属-卡宾键/羰基化序列3配位的3-indolylketenes 8,9,12-14,通过使用体积大的取代基; 反应速率随N-烷基化而增加。体积较小的n-炔基壬基碳烯配合物4,5表现出两个竞争的卡宾环化序列:苯并环合导致苯并[ a ]咔唑15、16,而没有事先羰基化的环戊环化提供茚并[1,2- b ]吲哚17、18。
Pd-Catalyzed Inter- and Intramolecular Carbene Transfer from Group 6 Metal−Carbene Complexes<sup>1</sup>
作者:Miguel A. Sierra、Juan C. del Amo、María J. Mancheño、Mar Gómez-Gallego
DOI:10.1021/ja002497i
日期:2001.2.1
intramolecular carbene transfer reactions has been studied. Thus, pentacarbonyl[(aryl)(methoxy)carbene]chromium(0) and tungsten complexes, 10, efficiently dimerize at room temperature in the presence of diverse Pd(0) and Pd(II)/Et(3)N catalysts. The effect of additives (PPh(3), AsPh(3), or SbPh(3)) on the nature and the isomeric ratio of the reaction products is negligible. The nature of the reaction products
pentacarbonyl[(2-N,N-dimethylamino)anilino(phenyl resp. 4-methylphenyl)carbene]chromium (1,2) leads to the formation of the tetracarbonyl carbene(C,N) complexes 3 and 4 which contain a six-membered chelate ring. These complexes react with internal alkynes to give either the tetracarbonyl(iminoindane-N,N) chelates 5 and 6 or the tricarbonyl(iminoindane) and -(aminoindene) complexes 7–10, respectively, depending
Reaction of complex ligands: Part 95. Chromium tricarbonyl complexes of polysubstituted naphthohydroquinones: regioselective synthesis via [3+2+1]-benzannulation and haptotropic rearrangement
A series of polysubstituted naphthohydroquinoid tricarbonyl chromiumcomplexes were prepared by chromium mediated [3+2+1]-benzannulation of Fischer-type carbenecomplexes with alkynes. The kinetics and the thermodynamic data of the η6-η6-haptotropic rearrangements were investigated by in-situ NMR spectroscopy. The free activation energies ΔG# range from 23 to 26 kcal mol−1 and only slightly depend