Organocatalytic oxa/aza-Michael–Michael Cascade Strategy for the Construction of Spiro [Chroman/Tetrahydroquinoline-3,3′-oxindole] Scaffolds
摘要:
A new useful and effective chiral amine-catalyzed oxa- and aza-Michael - Michael cascade methodology for the construction of enantiomerically enriched indolinones spiro-fused with chromans or tetrahydroquinolines is reported. By employing suitable organocatalysts depending on the different Michael donors (Ar-OH/Ar-NHR), the processes offered excellent stereocontrol (dr >20:1, >99% ee) under mild conditions.
Organocatalytic oxa/aza-Michael–Michael Cascade Strategy for the Construction of Spiro [Chroman/Tetrahydroquinoline-3,3′-oxindole] Scaffolds
摘要:
A new useful and effective chiral amine-catalyzed oxa- and aza-Michael - Michael cascade methodology for the construction of enantiomerically enriched indolinones spiro-fused with chromans or tetrahydroquinolines is reported. By employing suitable organocatalysts depending on the different Michael donors (Ar-OH/Ar-NHR), the processes offered excellent stereocontrol (dr >20:1, >99% ee) under mild conditions.
Nickel(II)‐Catalyzed Diastereo‐ and Enantioselective Michael/ Hemiacetalization Cascade Reaction of α‐Ketoesters with 2‐(2‐Nitrovinyl)phenols
作者:Long Chen、Wu‐Lin Yang、Jia‐Huan Shen、Wei‐Ping Deng
DOI:10.1002/adsc.201900753
日期:2019.10.8
A nickel(II)/diamine‐catalyzed diastereo‐ and enantioselective Michael/hemiacetalization cascade reaction of α‐ketoesters with 2‐(2‐nitrovinyl)phenols has been established, thus providing a range of structurally diverse polysubstituted chromanes in good yields and excellent stereoselectivities (up to 89% yield, >20:1 dr, >99% ee). Moreover, the gram‐scale experiment was performed with only 0.5 mol%