Molecular Sieve (MS 4A) Promoted Cyclocondensation of Hindered, Aromatic Nitrile Oxides and Cyclic Diketones under Mild Conditions

Tomoo Matsuura; Jeffrey W. Bode; Yoshifumi Hachisu; Keisuke Suzuki

doi:10.1055/s-2003-41436

LETTER

Molecular Sieve (MS 4A) Promoted Cyclocondensation of Hindered, Aromatic Nitrile Oxides and Cyclic Diketones under Mild Conditions

Tomoo Matsuura, Jeffrey W. Bode, Yoshifumi Hachisu, Keisuke Suzuki*
Department of Chemistry, Tokyo Institute of Technology and CREST, Japan Science and Technology Corporation, O-okayama, Meguro-ku, Tokyo 152-8551, Japan
Fax: +81(3)57342228; e-Mail: ksuzuki@chem.titech.ac.jp;

Abstract

All articles of this category

Abstract

Molecular sieves (MS 4A) serve as efficient promoters for the cyclocondensation of stable, hindered nitrile oxides and a variety of cyclic diketones to afford fused isoxazoles in good yield. The operational simplicity and remarkably mild reaction conditions compliment our amine-promoted cyclocondensation conditions and demonstrate broad substrate scope.

Key words

cycloadditions - ketones - condensation - isoxazoles - molecular sieves

Full Text

References

<A NAME="RU10903ST-1A">1a</A> Bode JW. Hachisu Y. Matsuura T. Suzuki K. Tetrahedron Lett. 2003, 44: 3555

<A NAME="RU10903ST-1B">1b</A> Bode JW. Hachisu Y. Matsuura T. Suzuki K. Org. Lett. 2003, 5: 391

<A NAME="RU10903ST-2">2</A> For a review of molecular sieve and zeolite promoted reactions, see: Sen SE. Smith SM. Sullivan KA. Tetrahedron 1999, 55: 12657

<A NAME="RU10903ST-3">3</A> The use of 4 Å MS as a base for the elimination of C-chloroximes to form nitrile oxides and subsequent cycloaddition with acrylates has been reported. However, under these conditions long reaction times (7-10 d) were necessary, see: Kim JN. Ryu EK. Heterocycles 1990, 31: 1693

MS 4A have the general formula Na₂O·Al₂O₃·xSiO₂·yH₂O.

<A NAME="RU10903ST-5">5</A> Thermal cycloadditions of 2-hydroxynaphthoquinone and nitrile oxides have been previously reported: Brahmeshwari G. Rao VR. Rao TVP. Indian J. Chem., Sect. B 1995, 34: 139

<A NAME="RU10903ST-6">6</A> Bode JW. Suzuki K. Org. Lett. 2003, 5: 394

<A NAME="RU10903ST-7">7</A> Hachisu Y. Bode JW. Suzuki K. J. Am. Chem. Soc. 2003, 125: 8432

<A NAME="RU10903ST-8">8</A> Bode JW. Suzuki K. Tetrahedron Lett. 2003, 44: 3559

<A NAME="RU10903ST-9">9</A> For a Diels-Alder type cycloaddition reaction promoted by molecular sieves, see: Pindur U. Haber M. Heterocycles 1991, 32: 1463