A Novel Route to Geminal Dibromocyclobutanes: Syntheses of 2-Substituted Cyclobutanone Acetals and Their Reaction with Boron Tribromide
作者:Tore Nordvik、Udo H. Brinker
DOI:10.1021/jo035295o
日期:2003.11.1
Nine 2-substituted cyclobutanone acetals, in addition to the parent cyclobutanone acetal, were synthesized from their corresponding cyclobutanones and subsequently treated with boron tribromide. The substituents were either alkyl chains or a phenyl and a benzyl group, respectively. The major compounds obtained in these reactions were, in most cases, the geminal dibromocyclobutanes which were obtained
除了母体环丁酮缩醛以外,还从它们相应的环丁酮合成了九个2-取代的环丁酮缩醛,随后用三溴化硼处理。取代基分别为烷基链或苯基和苄基。在大多数情况下,这些反应中获得的主要化合物是双溴双环丁烷,其收率在50%到73%之间。过量2倍的BBr3和在-78摄氏度下3小时的反应时间可提供最佳收率。在四种情况下,根本没有观察到二溴化物的形成,并且环丁酮缩醛被水解为相应的环丁酮。这可能是由于过渡态中乙缩醛和BBr3的位阻增加所致。