60154-53-2Relevant articles and documents
Cross-linked Poly-(4-vinylpyridine-styrene)-Bromine Complexes as Stereoselective Brominating Agents
Johar, Y.,Zupan, M.,Sket, B.
, p. 2059 - 2062 (2007/10/02)
Cross-linked poly(styrene-4-vinylpyridine) beads, containing 40-43percent 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 had no significant effect on stereoselectivity, but affects the reactivity, being significantly greater in acetonitrile and chloroform than in cyclohexane and dioxan.Bromination of 1-phenylcyclohexene with (1) and (3) resulted in the formation of trans-1,2-dibromo-1-phenylcyclohexane (9) and 3-bromo-2-phenylcyclohexene (10), the temperature affecting only the ratio of the products.Bromonation of norbornene with the reagents (1), (2) and (3) resulted in the formation of seven products: 2-exo-bromonorbornane (12), 7-bromonortricyclane (13), 2-exo,3-endo-dibromonorbornane (14), 2-exo-7-anti-dibromonorbornane (15), 2-exo,5-endo-dibromonorbornane (16), 2-exo,5-exo-dibromonorbornane (17), and 2-exo,7-syn-dibromonorbornane (18).
