Studies On Ring-Expansion Reaction Of Cyclobutenone Via Li/I Carbenoids

Recently,Li/Hal Carbenoid have become the hot research field. As a result of their special structures, they can react with such structures as C=C, C-C, C-H and so on,with rearrangement happened sometimes. Because the diversities revealed in reaction with each kind of compounds, they become the significant compounds to reorganize carbon skeleton.Specially, they have predominant stereoselectivity and region-selectivity, result in the sole goal product when they react with cyclo- compound.In recent years, it is reported that on the reactions of cyclobutanone series compounds with diazo carbenoids to give adducts of the cyclobutenone series compounds in many literatures. Refers to this kind of literatures, this article is performed firstly by diiodomethane and n -Butyllithium, with the Li/I Carbenoid as intermediate which react with cyclobutenone series compounds, utilizing the carbon cation's stabilization when it is rearranged due to double bonds, producing directly the sole rearranged and ring-expanding cyclopent-2-enone series compounds by one step. Compared with the reaction of the ring-enlargement of cyclobutanone series compounds to give cyclopent-2-enone by two steps which reported the recent years, it has less procedure, mild and safe reactive condition. It is initially carried on the planty of attempts on reactant allocated proportion, the solvent and so on which effect the reaction, and initially proposed the possible mechanism of reaction.