Stereocontrolled intramolecular ketone-olefin reductive coupling reactions promoted by samarium diiodide
作者:Gary A. Molander、Caryn Kenny
DOI:10.1016/s0040-4039(00)96511-0
日期:1987.1
The stereocontrolled intramolecular coupling of unsaturated β-ketoesters and β-ketoamides is reported. Good yields of highly substituted β-hydroxycyclopentanecarboxylates are generated in the process, with substantial and predictable stereochemical control at three contiguous stereocenters.
Sequential radical cyclization/intermolecular carbonyl addition reactions initiated by samarium(II) iodide
作者:Gary A. Molander、Caryn Kenny
DOI:10.1021/jo00004a020
日期:1991.2
A sequential reductive coupling process promoted by samarium (II) iodide (SmI2) is described. Thus, ethyl 2-acetyl-2-methyl-5-hexenoate, upon treatment with SmI2 in the presence of a variety of aldehydes or ketones, undergoes an initial radical (ketyl) olefin cyclization. Subsequent reduction of the intermediate radical generated in this process produces a transient organosamarium species which can be trapped in situ by the added aldehyde or ketone electrophiles. Through this sequential radical cyclization/intermolecular carbonyl addition reaction, two new carbon-carbon bonds are generated in a one-pot process. Furthermore, a high degree of stereochemical control is established over three contiguous stereocenters, markedly increasing molecular complexity from the starting materials to the observed products.