Synthese von 4,4-Bis(trifluormethyl)-1-oxabuta-1,3-dienen
摘要:
Silyl enol ethers (1) and hexafluoroacetone (2) react to give O-silylated aldol adducts 3 which, after desilylation with methanol/hydrochloric acid, are transformed into 4.4-bis(trifluoromethyl)-1-oxabuta-1,3-dienes (5) on treatment with trifluoroacetic acid anhydride/pyridine.
Title olefins are prepared by Wittig reactions between hexafluoroacetone and the methylenephosphoranes Ph3PCHX (X CN, CO2Me, COPh). They react readily with diazomethane or phenylazide affording pyrazolines or triazolines which are photodecomposed into the corresponding fluorocyclopropanes or aziridines. The latter compounds are potential azomethine ylides and react with methyl acetylene dicarboxylate
Synthesis of 3-trifluoromethylfurans from β,β-bis(trifluoromethyl)α,β-unsaturated ketones and tin(<scp>II</scp>) chloride
作者:Klaus Burger、Brigitte Helmreich
DOI:10.1039/c39920000348
日期:——
A new building block strategy for the synthesis of 3-trifluoromethyl-substituted furans 9 and 10 is described from β,β-bis(trifluoromethyl)α,β-unsaturated ketones 2via reductive fluoride elimination and 1,5-electrocyclization with elimination.
RfI(Ph)OSO2CF3 or RfI(Ph)OSO3H smoothly reacted with various trimethylsilyl enol ethers under mild conditions to give α-(perfluoroalkyl) carbonyl and γ=(perfluoroalkyl)-α,β-unsaturated carbonyl compounds in high yields.
R f I(Ph)OSO 2 CF 3或R f I(Ph)OSO 3 H在温和条件下与各种三甲基甲硅烷基烯醇醚平稳反应,得到α-(全氟烷基)羰基和γ=(全氟烷基)-α,β-不饱和羰基化合物的收率很高。
Rhodium-catalyzed α-fluoroalkylation reaction of ketones using silyl enol ethers
The treatment of silylenolethers with fluoroalkyl halides (Rf–X) in the presence of RhCl(PPh3)3 gave α-fluoroalkylated ketones. It seems that a rhodium complex derived from the silylenolether and RhCl(PPh3)3 played an important role for the oxidative addition of fluoroalkyl halides and the reductive elimination of the product.
在RhCl(PPh 3)3存在下用氟代烷基卤化物(R f –X)处理甲硅烷基烯醇醚,得到α-氟代烷基化的酮。似乎衍生自甲硅烷基烯醇醚和RhCl(PPh 3)3的铑配合物对于氟代烷基卤化物的氧化加成和产物的还原消除起着重要作用。
Cobalt-Catalyzed Hydroxyperfluoroalkylation of Alkenes with Perfluoroalkyl Bromides and Atmospheric Oxygen
for the cobalt-catalyzed hydroxyperfluoroalkylation of alkenes has been developed. This method demonstrated broad substrate scope, good yields, and mild conditions with the tolerance of mono-, di-, and trisubstituted alkenes including both styrenes and non-activated aliphatic olefins. This strategy offered a valuable solution for rapid and efficient construction of β-perfluoroalkyl alcohols using widely