A time-economical and robust synthesis of various selenofunctionalized heterocycles was accomplished via I2O5-mediated selenocyclizations of olefins with diselenides. Using this method, 116 selenomethyl-substituted heterocycles were synthesized with up to 97% isolated yield in minutes. Additional features of this new protocol include the use of an inorganic oxidant, mild conditions, and easy operation
通过I 2 O 5介导的烯烃与二硒化物的硒环化,实现了各种硒官能化杂环的经济且稳健的合成。使用这种方法,在几分钟内合成了 116 个硒甲基取代的杂环,分离产率高达 97%。这个新协议的其他特点包括使用无机氧化剂、温和的条件和易于操作。初步研究表明,这种转化是通过硒基碘诱导的亲电环化进行的。
Oligomerization and isomerization of olefins by catalysts derived from nickel complexes of dithio-β-diketonates
作者:Ramyani Abeywickrema、Martin A. Bennett、Kingsley J. Cavell、Michael Kony、Anthony F. Masters、Alison G. Webb
DOI:10.1039/dt9930000059
日期:——
The complexes [NiR1C(S)CR2C(S)R3}2] 1 and [Ni(R1C(S)CR2C(S)R3}(PL1L2L3)X] 2 (R, L = alkyl, aryl or CF3; X = Cl, Br or 1) have been prepared. The complexes 2 can be chemically anchored to polystyrene or silica-alumina supports via pendant phosphine ligands to form the derivatives 3. The species 2 and 3 in combination with a suitable co-catalyst form extremely active catalysts for the oligomerization of ethylene, propylene or butenes. The immobilised systems show no significant signs of leaching after 24 h operation. In general the oligomerization is highly selective to dimers, however, selectivity and catalyst activity are markedly affected by changes in L. Changes in R affect catalyst activity only.