4-甲基-3-戊烯酸置于吡啶,4-二甲氨基吡啶,Sodium Tetrahydroborate,正丁基锂,Ammonium Cerium(Iv) Nitrate,四溴化碳,三乙胺,三苯基膦,叔丁醇体系中,用 四氢呋喃,甲醇,正己烷,二氯甲烷,乙腈 作为反应溶剂,化学反应 10.24H,反应生成 紫草素
参考文献:A New Efficient Route For Multigram Asymmetric Synthesis Of Alkannin And Shikonin
标题:A New Efficient Route For Multigram Asymmetric Synthesis Of Alkannin And Shikonin
摘要:A Short And Convergent Approach For The Synthesis Of Alkannin,Shikonin And Shikalkin Is Presented. A Hauser-Type Annulation Of Cyanophthalide 26 With Enone 7 Affords The Complete Aromatic System In Just One Step With Concomitant Attachment Of The Entire Side Chain. Subsequent Corey'S Oxazaborolidine Mediated Asymmetric Reduction Of The Above Advanced Intermediate,Leads To The Required Isomer In High Enantiomeric Excess. Finally,A Selective And High Yielding Deprotection Protocol Furnishes The Title Compounds As Pure Crystalline Precipitates. Thus,A Multigram Synthesis Of Shikonin,Alkannin And Shikalkin Is Achieved In High Yield And Enantioselectivity.
DOI:10.1002/1521-3765(20020415)8:8<1795::Aid-Chem1795>3.0.Co;2-V