The Nucleophilicity of a Dialkylcarbene: Unusual Activation Parameters for Additions of Adamantanylidene to Simple Alkenes

Computational and experimental results demonstrate that adamantanylidene (1) behaves as a highly reactive nucleophile toward common alkenes. It is the only known saturated nucleophilic carbene that lacks direct or vinylogous heteroatomic substitution. The activation energy and enthalpy for addition of 1 to methyl acrylate are the most negative values yet encountered in any carbene–alkene addition.