Acid-Catalyzed Cyclization of Vinylsilanes Bearing a Hydroxy Group:  A New Method for Stereoselective Synthesis of Disubstituted Tetrahydrofurans1

• Published in: Journal of the American Chemical Society Vol. 122; no. 46; pp. 11348 - 11357
• Main Authors: Miura, Katsukiyo, Okajima, Shigeo, Hondo, Takeshi, Nakagawa, Takahiro, Takahashi, Tatsuyuki, Hosomi, Akira
• Format: Journal Article
• Language: English
• Published: American Chemical Society 22.11.2000
• ISSN: 0002-7863; 1520-5126
• DOI: 10.1021/ja002496q

In the presence of a catalytic amount of TsOH or TiCl4, (Z)-5-silyl-4-penten-1-ols ((Z)-1) are smoothly cyclized to 2-silylmethyl-substituted tetrahydrofurans. This cyclization is applicable to the construction of a tetrahydropyran ring. The silyl group and the geometry of the C−C double bond strongly influence the cyclization rate. TBDMS and benzyldimethylsilyl groups considerably accelerate the cyclization in comparison with a dimethylphenylsilyl group, and (E)-vinylsilanes show much lower reactivity than the corresponding (Z)-isomers. The cyclization proceeds by stereospecific syn addition of the hydroxy group. Vinylsilanes 17, 19, and 21, (Z)-5-silyl-4-penten-1-ols bearing a substituent on the methylene tether, smoothly undergo the acid-catalyzed cyclization to give trans-2,5-, cis-2,4-, and trans-2,3-disubstituted tetrahydrofurans, respectively, with moderate to high stereoselectivity. The silyl group of some cyclized products can be easily converted into a hydroxy group with stereochemical retention.