A new and generalsynthesis of ketene S,S-thioacetals (1) and ketene O.S-thioacetals (6) which involves the Horner-Wittig reaction of carbonyl compounds with the metallated S,S- and O,S-thioacetals of formyl-phosphonates (4 and 5) is described. The Horner-Wittig reaction of 4 with aromatic aldehydes can be carried out under two-phase conditions. The generation of the carbanions from 4 and 5 as well
烯酮S,S-硫缩醛(1)和烯酮OS-硫缩醛(6)的新的合成方法,涉及羰基化合物与甲酰基膦酸酯的金属化S,S-和O,S-硫缩醛的Horner-Wittig反应(4和5)被描述。4与芳族醛的霍纳-维蒂希反应可以在两相条件下进行。通过低温31 P NMR光谱研究了4和5中碳负离子的生成以及它们与羰基化合物的反应过程。已发现,甲酰基膦酸酯的S,S-硫缩醛(4)与甲膦酸酯的O,S-硫缩醛(5)相比非常容易金属化。)仅在用叔丁基锂处理时才能形成锂衍生物。从31 P NMR光谱中未获得证据支持形成甲酰基膦酸酯的0-0-缩醛的锂衍生物(12)。
The use of phosphonodithioformates for the synthesis of ketene dithioacetals
作者:Andrew Bulpin、Serge Masson、Aboubacary Sene
DOI:10.1016/s0040-4039(00)99259-1
日期:1989.1
Phosphonodithioformates 1 undergo thiophilic addition with both organolithium and Grignard reagents to give metallated dithioacetals of formyl-phosphonates 2, available for protonation, alkylation or use in Wittig-Horner reactions. Oxidation of 1 by meta-chloroperbenzoic acid leads to the corresponding sulphine 4 equally suitable for thiophilic addition.
[2 + 2] cycloadditions of 2,2-bis(trifluoromethyl)ethylene-1,1-dicarbonitrile with vinyl sulfides and ketene S,S-acetals
作者:Reinhard Brückner、Rolf Huisgen
DOI:10.1016/0040-4039(90)80125-6
日期:1990.1
In its [2+2] cycloadditions to vinyl sulfides, the title olefin (BTF) exceeds tetracyanoethylene up to 8200-fold in rate, but is more sensitive to steric hindrance by β-substituents in the donor olefin; some vinyl sulfides react faster than vinylethers with BTF. The dependence of rate on solvent polarity Is In harmony with zwitterionic Intermediates.
In the presence of certain Lewis acids, alkenes containing an alkylthio group (for example, ketene dithioacetals, alkenyl sulfides, alkynyl sulfides, and allenyl sulfides) react with electron deficient olefins to give the corresponding cyclobutane, cyclobutene, or methylene cyclobutane derivatives. By employing a chiral titanium catalyst generated in situ from dichlorodiisopropoxytitanium and a tartrate-derived chiral diol, the [2 + 2] cycloaddition reaction proceeds with high enantioselectivity.