【摘要】 联烯是含有 1,2 丙二烯官能团的重要化合物 ,具有很高的反应活性 .概述了联烯及其衍生物的自由基反应 ,包括分子间自由基链加成和分子间 -分子内自由基串联加成反应 ,及其在天然产物中的应用 .联烯进行分子间自由基链加成反应时 ,自由基对联烯的加成既可发生在中间碳原子上 ,也可发生在末端碳原子上 ,主要取于所形成中间体的稳定性 ,空间效应、电负性和溶剂等因素也有影响 .一般以碳为中心的自由基 (如CH3 · ,CCl3 ·等 )易进攻末端碳原子 ,而以杂原子为中心的自由基 (如Br· ,RS· ,ArSO2 ·等 )易进攻联烯的中心碳原子 .联烯及其衍生物也易与烯烃、联烯、烯炔和乙烯酮进行 [2 +2 ]环加成反应 ,还可以与卡宾环丙烷化 ,这些反应都是通过自由基机理进行的更多还原

【Abstract】 Allenes, which contain the functional group of 1,2-propadiene, are highly reactive. In this paper, we review some free-radical reactions of allenes. The application in natural product synthesis is also described. Substituted allenes undergo rather facile radical chain addition reactions. Attack by a radical species can occur at either the central or the terminal C atom. In the case of addition, the preferred route is generally that forming the possibly more stable free-radical intermediates. The steric effect, electronegativity and solvent effect shoulde also be considered. In general, carbon-centered free radicals such as CH 3· and CCl 3· add mostly to the terminal carbon atom while heteroatom-based free radicals such as Br·, RS·, ArSO 2· and R 3Sn· add preferentially to the central carbon atom. Substituted allenes can undergo a variety of [2+2] cycloaddition reactions with alkenes, allenes, enynes and ketenes and also undergo a cyclopropanation with carbenes via a biradical mechanism.更多还原