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Gold(I)‐Catalyzed Generation of the Two Components of a Formal [4+2] Cycloaddition Reaction for the Synthesis of Tetracyclic Pyrano[2,3,4‐ de ]chromenes
Author(s) -
Arto Tamara,
Fañanás Francisco J.,
Rodríguez Félix
Publication year - 2016
Publication title -
angewandte chemie international edition
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 5.831
H-Index - 550
eISSN - 1521-3773
pISSN - 1433-7851
DOI - 10.1002/anie.201602948
Subject(s) - cycloisomerization , stereocenter , cycloaddition , atom economy , catalysis , chemistry , diene , combinatorial chemistry , organic chemistry , enantioselective synthesis , natural rubber
Ortho ‐Alkynylbenzaldehydes have been widely used to generate isochromenylium derivatives through gold‐catalyzed cycloisomerization. These isochromenylium derivatives have been exploited as formal diene derivatives for reactions with different dienophiles. Herein, we describe the behavior of ortho ‐alkynylsalicylaldehydes, a particular case of ortho ‐alkynylbenzaldehydes. The gold‐catalyzed cycloisomerization of ortho ‐alkynylsalicylaldehydes delivers an unusual heterodiene derivative that reacts with electron‐rich alkenes through a formal [4+2] cycloaddition. In this reaction, both the diene and dienophile are generated in situ through gold‐catalyzed cycloisomerization of appropriate alkynamines or alkynols. This reaction was used to synthesize complex tetracyclic pyrano[2,3,4‐ de ]chromenes from two very simple starting materials (an ortho ‐alkynylsalicylaldehyde and an alkynamine or alkynol) with complete atom economy and with selective formation of bonds, cycles, and stereocenters.