An efficient synthesis of alpha,beta-unsaturated ketones by the reaction of acid chlorides with trialkylaluminum (1/3 mole equiv) in the presence of AlCl(3) (1 mol equiv) is described. Dialkylzincs were also useful and are easier to prepare than trialkylaluminum. Reaction of RCOCl with R'AlCl(2) or R'(2)AlCl gave R'COR, without AlCl(3), in high yield.
Rhodium-catalyzed 1,4-addition of alkenylzirconocene chlorides to electron deficient alkenes
作者:Akito Kakuuchi、Takeo Taguchi、Yuji Hanzawa
DOI:10.1016/j.tet.2003.08.073
日期:2004.2
acid esters, and α,β-enoic acid amides can be efficiently achieved by the use of [RhCl(cod)]2 catalyst. A high diastereoselectivity (95% yield, 90% de) was obtained through the reaction of α,β-enoic acid amide derived from Oppolzer'ssultam and 2-butenoyl chloride, while the use of Evans' chiral oxazolidinone as a chiral auxiliary in place of Oppolzer'ssultam gave a poor diastereoselectivity (98% yield
Rhodium-catalyzed isomerization of 1,3-diene monoepoxides to α,β-unsaturated carbonyl compounds
作者:Susumo Sato、Isamu Matsuda、Yusuke Izumi
DOI:10.1016/0022-328x(89)85435-x
日期:1989.1
α,β-Unsaturated aldehydes and ketones are readily formed by the rhodium(I) catalyzed isomerization of 1,3-diene monoepoxides. When RhH(PPh3)4 is used as a catalyst, only (E)-α,β-unsaturated carbonyl compounds are obtained selectively. The initial 1,3-diene monoepoxides are prepared regiospecifically from α-trimethylsilyl ketones by a two step procedure, bromination and subsequent vinylative epoxidation
purpose of exploring a new reaction of acylzirconocene chloride as an acyl anion donor, Cu(I)-catalyzed cross-coupling and conjugate additionreactions of acylzirconocene chloride were studied. The coupling reaction with allylic or propargylic halides efficiently proceeded to yield β,γ-unsaturated ketone or allenyl ketone derivatives, respectively. The conjugated additionreaction to α,β-enones was carried
Reported here for the first time are the oxidative couplings of alkynes and primary alcohols yielding conjugated enones. Although the BF3-catalyzed reaction of terminal alkynes with p-trifluoromethylphenyl(difluoro)-lambda3-bromane results in the fluoro-lambda3-bromanation of triple bonds to afford (E)-beta-fluorovinyl-lambda3-bromanes, reaction of an alkyne with the difluoro-lambda3-bromane in the