Diastereoselectivity of the thio-Claisen rearrangement of acyclic precursors bearing a chiral centre adjacent to carbon 6
作者:Stéphane Désert、Patrick Metzner
DOI:10.1016/s0040-4020(01)88337-x
日期:1992.11
allylic alcohols have been prepared and submitted to a Mitsunobu reaction with dithioacetic acid. Allyl dithioesters were deprotonated by LDA at −30°C and resulting enethiolates were quenched with iodomethane to afford quantitatively S-allyl ketenedithioacetals. These precursors undergo a thio-Claisen rearrangement under smooth conditions: room temperature or heating at 101°C. The diastereoselectivity of
已经制备了许多手性烯丙基醇,并使其与二硫代乙酸进行Mitsunobu反应。在-30℃下通过LDA使烯丙基二硫代酸酯去质子化,并将所得的烯硫醇化物用碘甲烷淬灭,以定量地提供S-烯丙基烯酮二硫缩醛。这些前体在光滑条件下进行硫代克莱森重排:室温或101°C加热。关于立体发生中心的两个取代基的性质,研究了这种σ位移的非对映选择性。对于甲基和叔丁基,观察到75:25的比例,并通过空间位阻来解释。对于各种烷氧基,我们观察到非常适度的选择性,有利于顺式非对映异构体。