Tetrahedron

A new procedure for highly stereoselective and regioselective synthesis of 2-ethynyl-3-hydroxytetrahydropyran derivatives based on alkyne-Co 2 (CO) 6 complex

C Mukai, Y Sugimoto, Y Ikeda, M Hanaoka

Index: Mukai, Chisato; Sugimoto, Yu-Ichi; Ikeda, Yoshitaka; Hanaoka, Miyoji Tetrahedron, 1998 , vol. 54, # 5-6 p. 823 - 850

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Citation Number: 45

Abstract

Treatment of trans-epoxides 3 with Co2 (CO) 8 gave the corresponding cobalt complexes, which were subsequently exposed to a catalytic amount of BF3· OEt2 at− 78° C to provide exclusively cis-2-ethynyl-3-hydroxytetrahydropyran derivatives via endo mode cyclization pathway. cis-Congeners, cis-3 afforded the corresponding trans tetrahydropyran derivatives exclusively. This novel cyclization has been found to proceed with retention of ...