Cochran Brian M, Michael Forrest E
Department of Chemistry, University of Washington, Box 351700, Seattle, Washington 98195-1770, USA.
Org Lett. 2008 Nov 6;10(21):5039-42. doi: 10.1021/ol8022165. Epub 2008 Oct 9.
A metal-free oxidative cyclization of ureas onto unactivated alkenes using iodosylbenzene and an acid promoter is described. The products isolated are predominantly bicyclic isoureas resulting from an intramolecular oxyamination reaction. The acid type and urea substitution have a strong effect on the product formed. A variety of substrates form the isourea with high diastereoselectivity via syn addition including di- and trisubstituted alkenes. Hydrolysis of the isourea gives access to new diastereomerically pure prolinol derivatives.
描述了一种使用亚碘酰苯和酸性促进剂将脲进行无金属氧化环化到未活化烯烃上的反应。分离得到的产物主要是由分子内氧胺化反应产生的双环异脲。酸的类型和脲的取代基对形成的产物有很大影响。通过顺式加成，多种底物能以高非对映选择性形成异脲，包括二取代和三取代烯烃。异脲的水解可得到新的非对映体纯的脯氨醇衍生物。
