C,C-coupling with sulfur-stabilized carbanions — 6. Preparation and electrophilic substitution of 1-[3-methyl-2-(2-thiolanylthio)-butyl]piperidine and dethioacetalization of semicyclic dithioacetals,
作者:C Birk
DOI:10.1016/0040-4020(96)00757-0
日期:1996.9.23
dithioacetals 12 – 15 are converted into the corresponding carbonyl compounds with [bis(trifluoroacetoxy)iodo]benzene (PIFA). Phenyl dichlorophosphate (PDCP) in the presence of sodium iodide and DMF is found to be a reagent for selective cleavage of the exocyclic CS bond. By using DOWEX 50W and paraformaldehyde in acetone/water a cleavage of both acetalic CS bonds is achieved in certain cases.
通过对映体纯的1-(2-巯基-3-甲基丁基)哌啶(6)从L-缬氨酸获得1- [3-甲基-2-(2-硫代丙氨硫基)丁基]哌啶(8)。通过柱色谱分离非对映异构体,并研究碳负离子8a与亲电试剂的反应。半环二硫缩醛12-15与[双(三氟乙酰氧基)碘]苯(PIFA)转化为相应的羰基化合物。发现在碘化钠和DMF存在下的二氯磷酸苯酯(PDCP)是选择性裂解环外CS键的试剂。在某些情况下,通过在丙酮/水中使用DOWEX 50W和低聚甲醛,可以实现两个缩醛CS键的裂解。