Asymmetric Pauson−Khand Reactions Using Camphor-Derived Chelating Thiols as Chiral Controllers
作者:Iolanda Marchueta、Elvira Montenegro、Dmitri Panov、Marta Poch、Xavier Verdaguer、Albert Moyano、Miquel A. Pericàs、Antoni Riera
DOI:10.1021/jo015790p
日期:2001.9.1
(1S)-camphor-10-thiol has been developed. The ethynyl derivatives of these thiols gave excellent diastereoselectivities (up to 98:2) in Pauson-Khand reactions with norbornene and norbornadiene through the intermediacy of a chelated dicobalt pentacarbonyl complex. Thermal reaction conditions starting from the preformed chelated complex gave better results than N-oxide-promoted runs with in situ generation of
已开发了一种从(1S)-樟脑10硫醇制备对映体纯的10-(R-硫基)-2-exo-降冰片烷硫醇的简便方法。这些硫醇的乙炔基衍生物通过螯合的二钴二羰基五羰基络合物的中间体在与降冰片烯和降冰片二烯的Pauson-Khand反应中具有出色的非对映选择性(高达98:2)。从预形成的螯合配合物开始的热反应条件比采用原位生成螯合中间体的N-氧化物促进的运行更好。通过包括缀合物加成,碘化sa促进的手性助剂的裂解和逆狄尔斯-阿尔德反应组成的方案详细说明了相应的加合物,以得到高对映体纯度的4-取代的2-环戊烯酮。