Surprisingly great difference in reactivity depending upon the ring size: solvolysis and molecular structure study of some N-trimethylsilylated cyclic ureas

The molecular structure and the octanolysis rate of N-trimethylsilylated cyclic ureas was studied. The half-lives of the five-membered rings are at least three orders of magnitude higher than those of the six- and seven-membered analogues. Relationship between the reactivity and the extent of the pseudo-pentacoordination around silicon was found.