Regio- and stereoselective behavior of L-arabinal-derived vinyl epoxide in nucleophilic addition reactions. Comparison with conformationally restricted D-galactal-derived analogs

TETRAHEDRON

卷:71

Article

Di Bussolo, Valeria¹  Frau, Ileana¹  Favero, Lucilla¹  Uccello-Barretta, Gloria²  Balzano, Federica²  Crotti, Paolo¹ 

[1] Univ Pisa, Dipartimento Farm, I-56126 Pisa, Italy

[2] Dipartimento Chim & Chim Ind, I-56124 Pisa, Italy

关键词: Vinyl epoxides;    Glycals;    Regioselectivity;    Stereoselectivity;    L-Sugars;   

DOI  :  10.1016/j.tet.2015.06.057

来源: Elsevier

【 摘 要 】

The regio- and stereoselectivity of the addition reactions of O-, C-, N-, and S-nucleophiles to L-arabinal-derived vinyl epoxide 2, the simplest non-conformationally restricted glycal-derived vinyl epoxide, has been examined and compared with the corresponding, conformationally restricted D-galactal-derived analogs 1 beta and 1 beta-Me. Results indicated that the 1,4-/1,2-regioselectivity ratio and the related syn-1,4-/anti-1,2-stereoselectivity observed in glycal-derived vinyl oxiranes is independent of the presence of substituents on the six-membered unsaturated ring, and the absence of conformational freedom: it depends only on the ability of the nucleophile to give a coordination process with the oxirane oxygen in the form of a hydrogen bond or through a coordinating cation. (C) 2015 Elsevier Ltd. All rights reserved.

【 授权许可】

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