Copper(II)-Catalyzed Asymmetric Henry Reaction of <i>o</i>-Alkynylbenzaldehydes Followed by Gold(I)-Mediated Cycloisomerization: An Enantioselective Route to Chiral 1<i>H</i>-Isochromenes and 1,3-Dihydroisobenzofurans
作者:Dengfu Lu、Yirong Zhou、Yajun Li、Shaobai Yan、Yuefa Gong
DOI:10.1021/jo201596p
日期:2011.11.4
By combining the copper(II)-catalyzed asymmetric Henry reaction of o-alkynylbenzaldehydes with subsequent gold(I)-catalyzed cycloisomerization, optically active 1H-isochromenes and 1,3-dihydroisobenzofurans were successfully synthesized in good overall yields with good to excellent enantioselectivities (up to 98%). Various substrates were investigated, and a correlation between the regioselectivity
通过将铜(II)催化的邻炔基苯甲醛的不对称亨利反应与随后的金(I)催化的环异构化反应相结合,成功以良好的总收率和良好的对映选择性成功合成了光学活性的1 H-异色酮和1,3-二氢异苯并呋喃(高达98%)。研究了各种底物,并研究了底物的区域选择性和电子性质之间的相关性。在炔基部分具有供电子基团的底物优选采用6内切-挖掘方式生成1 H-异色酮3作为主要产物(最高> 30:1),而具有吸电子基团的底物倾向于经历5 --exo - dig环化反应生成1,3-二氢异苯并呋喃4(最高达1:5)。