Catalytic asymmetric hydrogenation of indoles using a rhodium complex with a chiral bisphosphine ligand PhTRAP
作者:Ryoichi Kuwano、Manabu Kashiwabara、Koji Sato、Takashi Ito、Kohei Kaneda、Yoshihiko Ito
DOI:10.1016/j.tetasy.2006.01.016
日期:2006.2
Highly enantioselective hydrogenation of N-protected indoles was successfully developed by use of the rhodium catalyst generated in situ from [Rh(nbd)2]SbF6 and the chiral bisphosphine PhTRAP, which can form a trans-chelate complex with a transition metal atom. The PhTRAP–rhodium catalyst required a base (e.g., Cs2CO3) for the achievement of high enantioselectivity. Various 2-substituted N-acetylindoles
通过使用由[Rh(nbd)2 ] SbF 6原位生成的铑催化剂和手性双膦PhTRAP,可以成功地开发出N-保护的吲哚的高度对映选择性氢化反应,可以与过渡金属原子形成反式-螯合物。PhTRAP-铑催化剂需要碱(例如Cs 2 CO 3)才能实现高对映选择性。将各种2-取代的N-乙酰吲哚转化为具有高达95%ee的相应的手性二氢吲哚。3-取代的N - tosylindoles的氢化产生二氢吲哚,其在3-位具有立体异构中心,具有高的对映异构体过量(至多98%ee)。