Highly Selective Nucleophilic 4-Aryl-2,3-allenylation of Malonates

• 作者: Shihua Song Shengming Ma
• 来源期刊: 中国化学（英文版）
• 年，卷（期）: 2020,（11）
• 所属期刊栏目: Breaking Report
• 页码范围: 1233-1238
• 页数: 6页
• 语种: 英文
• DOI: 10.1002/cjoc.202000300

摘要

Allenes are a class of very important compounds and the development of straightforward,efficient,and highly enantioselective synthetic strategies for allenes have attracted extensive interests.Along this line,it is well known that aryl-substituted allenes may be readily racemized,thus,difficult to prepare in high ee.Herein,an efficient palladium-catalyzed nucleophilic allenylation of malonates with racemic 4-aryl-2,3-butadienyl carbonates has been developed.The selectivity issue of mono-vs.bis-allenylation with 2-non-substituted malonates has been ad-dressed.By utilizing(R)-(-)-DTBM-SEGPHOS(5,5'-bis[di(3,5-di-t-butyl-4-methoxyphenyl)phosphino]-4,4'-bi-1,3-benzodioxole)as a chiral ligand,various aryl-substituted allenes and bisallenes have been prepared with good to excellent yields with high chemoselectivity and enantioselectivity under mild reaction conditions.Au-catalyzed cycloisomerization and APK(allenic Pauson-Khand)reactions affording optically active mono-and bicyclic products have been demonstrated.