Diastereoselective Addition of Allyl- and Crotylstannanes to Dicobalt-Complexed Acetylenic Aldehydes
作者:Sonya Balduzzi、Michael A. Brook、Michael J. McGlinchey
DOI:10.1021/om050019g
日期:2005.5.1
In an endeavor to utilize metal carbonyl complexes of acetylenic aldehydes and ketones to control the stereoselectivity of nucleophilic acyl addition, the dicobalt hexacarbonyl and dicobalt pentacarbonyl(triphenylphosphine) complexes of 3-phenylpropynal and 2-hexynal were conveniently prepared. Crotyl transfer from either (E)- or (Z)-crotyltributylstannane to Co2(CO)6-complexed 3-phenylpropynal and
为了利用乙炔醛和酮的金属羰基配合物控制亲核酰基加成的立体选择性,方便地制备了3-苯基丙炔和2-己炔的二羰二羰六羰基和二羰五羰基三苯基膦(三苯基膦)配合物。从(E)-或(Z)-巴豆基三丁基锡烷的巴豆基转移至Co 2(CO)6-络合的3-苯基丙炔和2-己炔醛产生具有高合成非对映选择性的3,4-二取代-1,5-烯炔。烯丙基和2-甲基烯丙基转移至Co 2(CO)5 PPh 3还以高收率和非对映选择性完成了络合醛。在所有情况下,在非常温和的氧化条件下选择性地进行羰基金属部分的分解。PPh 3交换CO导致整体反应性降低。观察到两个竞争的动力学过程:在低温下观察到立体选择性烯丙基化,但在更高的温度下,首先形成的烯丙基醇优先经历消除反应而生成二烯。