Enantioselective Synthesis of Chromanones via a Tryptophan- Derived Bifunctional Thiourea-Catalyzed Oxa-Michael-Michael Cascade Reaction
作者:Haifei Wang、Jie Luo、Xiao Han、Yixin Lu
DOI:10.1002/adsc.201100419
日期:2011.11
Tryptophan-derived tertiary amine-thiourea catalysts were shown to promote a cascade oxa-Michael–Michael reaction between ethylene β-keto esters and nitroolefins, resulting in the formation of 3,3-disubstituted 4-chromanones bearing a quaternary center in high diastereoselectivity and enantioselectivity. The chromanone products can be readily converted to biologically important fused and spiro tricyclic
色氨酸衍生的叔胺-硫脲催化剂可促进乙烯β-酮酯与硝基烯烃之间的级联oxa-Michael-Michael反应,导致形成具有高非对映选择性和四级中心的3,3-二取代的4-苯并二氢呋喃酮。对映选择性。苯并二氢吡喃酮产物可以容易地转化为生物学上重要的稠合和螺三环苯并二氢吡喃。