Sulfur ylides. 4. Cyclopropanation of fulvenes by ethyl (dimethylsulfuranylidene)acetate under interphase catalysis conditions
摘要:
The reaction was studied of fulvenes with ethyl (dimethylsulfuranylidene)acetate generated under interphase catalysis conditions from the sulfonium salt [MeS+CH2-CO2Et)]Br- by the action of 85% KOH in the presence of triethylbenzylammonium chloride.
(R=R′=Ph) were determined. In the neutral complexes the non-planar fulvene ligands are essentially η4-coordinated with short uncoordinated exocyclic carbon–carbon double bonds. In contrast, the protonated species exhibit η5-coordinated planar five-membered rings. Using cyclic voltammetry, the complexes 3e,f and 9 were shown to reversibly undergo one-electron oxidation and reduction reactions to give the cations
五烯酮配合物[(C 5 R 5)Co(C 6 H 4 R'R'')] 3d(R = H,R'= Me,R''= Ph),3f(R = H,R'= Ph,R''= C 6 H 4 NO 2 -4),3g(R = H,R'= R''= SMe)和9(R = Me,R'= R''= Ph)制备各自的fulvenes和[(C 5 R 5)Co(C 2 H 4)2 ] 8a,b。在富勒烯C-α处发生3的质子化,生成取代的钴ce阳离子。的晶体和分子结构确定了3g,9和质子化产物[ 3e + H] +(R = R'= Ph)。在中性配合物的非平面富烯配体是基本上η 4与短不协调环外的碳-碳双键的配位的。与此相反,质子化的物种表现出η 5配位的平面五元环。使用循环伏安法,显示配合物3e,f和9可逆地进行单电子氧化和还原反应,得到阳离子[ 3e ] +,[ 3f ] +,[ 9 ] +阴离子[ 3e ] -,[
Synthetic Attempts towards Polymers with Pentafulvene Structural Units
作者:Gengyi Zhang、Markus Neuenschwander
DOI:10.1002/hlca.19950780506
日期:1995.8.9
Syntheticattemptstowards fully conjugated polymers 9 with pentafulvene-diyl structural units are described. Cationic polymerization of pentafulvenes 1a (R = X = Me) and 1b (R = X = MeS) nearly quantitatively gives polymers 8a and 8b with typical Mn and Mw values of 38800 and 53750, respectively, for 8a, and 12000 and 35900, respectively, for 8b. Key step of the conversion 8a 9a (Scheme 6) is a quantitative
Diels–Alder reactions of (trimethoxymethyl)cyclopentadienes. Formation of adducts derived from the 2-substituted tautomer
作者:Peter Yates、Indranil Gupta
DOI:10.1039/c39810000449
日期:——
The 1:2:1 tautomeric mixture of 2- and 1-(trimethoxymethyl)cyclopentadienes, when treated with dimethyl acetylenedicarboxylate, p-benzoquinone, and methyl propiolate, gave adducts derived largely from the 2-substituted tautomer; more reactive dienophiles gave 2:1 mixtures of adducts derived from the 2- and 1- substituted tautomers, respectively.