Rhodium-catalysed asymmetric ring opening of oxabicyclic alkenes with heteroatom nucleophiles
作者:Mark Lautens、Keith Fagnou、Mark Taylor、Tomislav Rovis
DOI:10.1016/s0022-328x(00)00904-9
日期:2001.4
high regio- and diastereoselectivity (>99:1), and excellent enantioselectivity (up to 99%ee). Symmetrical substitution patterns on the aromatic ring of the oxabenzonorbornadienes had no effect on the course of the reaction nor the enantioselectivity. The reaction produces an unusual stereochemical outcome for oxabicyclic ring openings since the trans rather than the cis product is formed. Very low catalyst
我们描述了一种新的铑催化的氧杂苯并降冰片二烯的不对称开环(ARO)反应。该反应通过桥头氧与多种醇和酚的分子间烯丙基置换产生新的碳-氧键。该反应在中性反应条件下发生,不需要醇亲核试剂的活化。它具有很高的区域选择性和非对映选择性(> 99:1)和出色的对映选择性(高达99%ee)。氧杂苯并降冰片二烯的芳环上的对称取代图案对反应过程和对映选择性没有影响。由于反式而不是顺式,该反应对氧杂双环开环产生不同寻常的立体化学结果产品形成。可以使用非常低的催化剂负载量,通常为催化活性铑物质的0.25摩尔%。