Fe(III) Halides as Effective Catalysts in Carbon−Carbon Bond Formation: Synthesis of 1,5-Dihalo-1,4-dienes, α,β-Unsaturated Ketones, and Cyclic Ethers
作者:Pedro O. Miranda、David D. Díaz、Juan I. Padrón、Miguel A. Ramírez、Víctor S. Martín
DOI:10.1021/jo048410j
日期:2005.1.1
homopropargylic alcohols were used, a Prins-type cyclization occurred yielding 2-alkyl-4-halo-5,6-dihydro-2H-pyrans. In addition, anhydrous ferric halides are also shown to be excellent catalysts for the standard Prins cyclization with homoallylic alcohols. Isolation of an intermediate acetal, calculations, and alkyne hydration studies provide substantiation of a proposed mechanism.
卤化铁(III)被证明是乙炔和醛偶联的极好催化剂。当使用末端乙炔时,获得的主要产物是1,5-二卤代1,4,4-二烯,其中(E,Z)-立体化学在某些情况下被(E)-α,β-不饱和酮污染。当使用非末端芳烃时,前者的羰基衍生物是唯一分离出的产物。当使用高炔丙醇时,发生Prins型环化反应,生成2-烷基-4-卤代-5,6-二氢-2 H-pyrans。另外,无水卤化铁也被证明是用均烯丙基醇进行标准Prins环化的极佳催化剂。中间缩醛的分离,计算和炔烃水合研究为提出的机理提供了依据。