An Unprecedented Stereoselective Titanium-Mediated Dihydrodimerization of Allyl Ethers and Allylamines
作者:Armin de Meijere、Björn Stecker、Alexandre Kourdioukov、Craig M. Williams
DOI:10.1055/s-2000-6297
日期:——
3-Phenylallyl ether 17, 2,5-dihydrofuran (1) and N-acceptor-substituted 2,5-dihydropyrrols 4, 6, 8, 10, 12 upon treatment with cyclohexylmagnesium bromide in the presence of Ti(Oi-Pr)4 were found to undergo a diastereoselective dihydrodimerization affording 1,5-dienes, d,l-2,3-diethenylbutane-1,4-diol (51% yield) and d,l-2,3-diethenyl-1,4-bis(sulfonylamino)butanes (43 - 52%), respectively. In the presence of titanium bis(4R,5R)-taddolate, the dihydrodimerization of 1 proceeded with 35 - 38% chemical yield and up to 94% ee.
在 Ti(Oi-Pr)4存在下,用环己基溴化镁处理 3-苯基烯丙基醚 17、2,5-二氢呋喃(1)和 N-受体取代的 2,5-二氢吡咯 4、6、8、10、12 后,发现它们会发生非对映选择性二氢二聚化,生成 1、5-二烯、d,l-2,3-二乙烯基-1,4-丁二醇(产率 51%)和 d,l-2,3-二乙烯基-1,4-双(磺酰氨基)丁烷(产率 43 - 52%)。在双(4R,5R)-涕灭酸钛存在下,1 的二氢化二聚反应以 35 - 38% 的化学收率进行,ee 值高达 94%。