Functionalization of Csp3–H bond—Sc(OTf)3-catalyzed domino 1,5-hydride shift/cyclization/Friedel–Crafts acylation reaction of benzylidene Meldrum’s acids
摘要:
Under Sc(OTf)(3) catalysis, benzylidene Meldrum's acids bearing a tethered p-methoxyphenethyl group were observed to undergo a [1,5]-hydride shift/cyclization at room temperature, representing a mild Csp(3)-H bond functionalization. The resulting spiro Meldrum's acid intermediates then underwent intramolecular Friedel-Crafts acylation, completing the one-pot, domino reaction. The reported protocol generates the 6-6-5-6 tetracyclic core of tetrahydrobenzo[b]fluoren-11-ones. (C) 2009 Elsevier Ltd. All rights reserved.
Functionalization of Csp3–H bond—Sc(OTf)3-catalyzed domino 1,5-hydride shift/cyclization/Friedel–Crafts acylation reaction of benzylidene Meldrum’s acids
摘要:
Under Sc(OTf)(3) catalysis, benzylidene Meldrum's acids bearing a tethered p-methoxyphenethyl group were observed to undergo a [1,5]-hydride shift/cyclization at room temperature, representing a mild Csp(3)-H bond functionalization. The resulting spiro Meldrum's acid intermediates then underwent intramolecular Friedel-Crafts acylation, completing the one-pot, domino reaction. The reported protocol generates the 6-6-5-6 tetracyclic core of tetrahydrobenzo[b]fluoren-11-ones. (C) 2009 Elsevier Ltd. All rights reserved.
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 Henryreaction 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