Enantioselective Construction of New Chiral Cyclic Scaffolds Using [2 + 2 + 2] Cycloaddition (Report)
Pure and Applied Chemistry 2011, March, 83, 3
Pure and Applied Chemistry
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INTRODUCTION The transition-metal-catalyzed [2 + 2 + 2] cycloaddition of alkynes is the most atom-economical and facile protocol for the construction of a benzene ring. Yamazaki is a pioneer in this field and reported the cobalt complex-mediated trimerization of diphenylacetylene . Vollhardt reported a catalytic reaction using cobalt carbonyl complex: this reaction offered a new route for the preparation of substituted benzenes by alkyne trimerization . As for an enantioselective [2 + 2 + 2] cycloaddition of alkynes, Mori reported the chiral nickel complex-catalyzed intermolecular reaction of triynes with acetylene: in this reaction, an asymmetric carbon atom was generated at the benzylic position of the obtained benzene ring by enantiotopic group selection . Stary reported the chiral nickel complex-catalyzed intramolecular reaction of triynes, which induced helical chirality . Even though these were pioneering and fascinating works, enantioselectivity was not sufficiently high. In 2004, three groups including ours independently reported enantioselective [2 + 2 + 2] cycloaddition using chiral cobalt, iridium, and rhodium catalysts, respectively, for the induction of axial chirality . Since then, various types of enantioselective [2 + 2 + 2] cycloaddition have been comprehensively studied by us and other groups . This manuscript discloses two approaches based on the [2 + 2 + 2] cycloaddition of triynes for the construction of new chiral scaffolds.
- Category: Chemistry
- Published: Mar 01, 2011
- Publisher: International Union of Pure and Applied Chemistry
- Seller: The Gale Group, Inc.
- Print Length: 9 Pages
- Language: English