Methylidene, cycloalumination

For a long period of time after the discovery of catalytic cycloalumination of imsaturated compounds, 1,1-disubstituted olefins were considered to be nonreactive in these reactions. It was suggested [175] that unlike acyclic olefins with low-reactivity 1,1-disubstituted double bonds, strained cyclic unsaturated compounds with an activated methylidene bond, for example, methylidene cyclobutanes or methylidene cyclopropanes, would react with EtsAl in the presence of transition... 

The catalytic cycloalumination reactions developed for strained methylidene cycloalkanes were employed for the development of a general one-pot method... 

Scheme 37 Catalytic cycloalumination of methylidene and alkylidene cyclopropanes...

Scheme 40 Catalytic cycloalumination of strained methylidene cycloalkanes in the synthesis of spiro[2.3]hexanes and spiro[3.3]heptanes...

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