Cross-linked poly-(4-vinylpyridine–styrene)–bromine complexes as stereoselective brominating agents
作者:Y. Johar、M. Zupan、B. Šket
DOI:10.1039/p19820002059
日期:——
containing 40–43% of pyridine rings, were transformed with bromine to provide three types of brominating agents (1), (2), and (3). Reactions of cis- and trans-1-phenylpropene with (1), (2), and (3) resulted in a high degree of anti-stereoselectivity. The reactivity increases from (1) to (3); solvent polarity has no significant effect on stereoselectivity, but affects the reactivity, being significantly greater
用溴转化含有40-43%吡啶环的交联聚苯乙烯-4-乙烯基吡啶珠,以提供三种类型的溴化剂(1),(2)和(3)。的反应顺式-和反式-1-苯基丙烯与(1),(2),(3)导致了高度的抗-stereoselectivity。反应性从(1)增加到(3);溶剂的极性对立体选择性没有显着影响,但会影响反应性,乙腈和氯仿中的环氧基和二恶烷中的环氧基显着更大。1-苯基环己烯与(1)和(3)的溴化反应导致反式的形成-1,2-二溴-1-苯基环己烷(9)和3-溴-2-苯基环己烯(10),温度仅影响产物的比例。用试剂(1),(2)和(3)溴降冰片烯的溴化反应形成了七种产物:2-外-溴降冰片烷(12),7-溴三环烷(13),2-外-溴,3-内- dibromonorbornane(14),2- exo -7-抗dibromonorbornane(15),2- exo,5-内-dibromonorbornane(16),2-