Copper(II)-Catalyzed Asymmetric Henry Reaction of o-Alkynylbenzaldehydes Followed by Gold(I)-Mediated Cycloisomerization: An Enantioselective Route to Chiral 1H-Isochromenes and 1,3-Dihydroisobenzofurans
Copper(II)-Catalyzed Asymmetric Henry Reaction of o-Alkynylbenzaldehydes Followed by Gold(I)-Mediated Cycloisomerization: An Enantioselective Route to Chiral 1H-Isochromenes and 1,3-Dihydroisobenzofurans
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DOI：
10.1021/jo201596p
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发表时间：
2011-11-04
影响因子：
3.6
通讯作者：
Gong, Yuefa
中科院分区：
文献类型：
--
作者：
Lu, Dengfu;Zhou, Yirong;Gong, Yuefa
将铜（II）催化的邻炔基苯甲醛的不对称Henry反应与金(I)催化的环异构化反应结合，成功地合成了具有光学活性的1h -异色胺和1,3-二氢异苯并呋喃，总收率高，对映选择性高（可达98%）。研究了各种底物，并研究了底物的区域选择性与电子性质之间的关系。在炔基上具有供电基团的底物倾向于以6-外显方式生成1h -异色胺3作为主要产物（比例为30:1），而具有吸电子基团的底物倾向于以5-外显方式生成1,3 -二氢异苯并呋喃4（比例为1:5）。
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 and electronic nature of the substrates was studied. The substrates with electrodonating groups at the alkynyl moiety preferred a 6-endo-dig manner to generated 1H-isochromenes 3 as main products (up to >30:1) while the ones with electron-withdrawing groups were inclined to undergo 5-exo-dig c-yclization to form I,3-dihydroisobenzofurans 4 (up to 1:5).