The electron-deficient olefin 2,2-bis(trifluoromethyl)ethylene-1,1-dicarbonitrile: hydride abstractions from allyl and isobutenyl ethers and thioethers
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.
Efficient transformations of trithio- and triseleno-orthoesters into ketene dithio- and diseleno-acetals
作者:K. M. Nsunda、L. Hevesi
DOI:10.1039/c39850001000
日期:——
Sequential treatment of trithio- and triseleno-orthoesters with a Lewis acid followed by a base leads to ketenedithio- and diseleno-acetals in good yield; SnCl4 or TiCl4 and Pri2EtN or Et3N are the most efficient reagents.
A stable, crystalline carbenium iodide, which possesses a thiocarbonyl group at the β-position, shows ambident reactivities, thereby reacting with a hard nucleophile OH− at the carbenium carbon atom and with a soft nucleophile RLi at the thiocarbonyl sulfur atom. Thermal dissociation of the MeLi adduct to a carbene and a ketene dithioacetal is also presented.