Solvolysis of (Z)-5-trimethylstannyl 2-adamantyl p-bromobenzenesulfonate: mechanistic implications of a record-breaking secondary alpha-deuterium kinetic isotope effect for an SN1 substrate

William Adcock; Neil A Trout; David Vercoe; Dennis K Taylor; V J Shiner Jr; Ted S Sorensen

doi:10.1021/jo0300892

Solvolysis of (Z)-5-trimethylstannyl 2-adamantyl p-bromobenzenesulfonate: mechanistic implications of a record-breaking secondary alpha-deuterium kinetic isotope effect for an SN1 substrate

J Org Chem. 2003 Jun 27;68(13):5399-402. doi: 10.1021/jo0300892.

Authors

William Adcock¹, Neil A Trout, David Vercoe, Dennis K Taylor, V J Shiner Jr, Ted S Sorensen

Affiliation

¹ School of Chemistry, Physics, and Earth Sciences, Flinders University of South Australia, Adelaide, SA 5001, Australia. william.adcock@flinders.edu.au

PMID: 12816508
DOI: 10.1021/jo0300892

Abstract

The secondary alpha-deuterium kinetic isotope effect (alpha-kie) for the solvolysis of (Z)-5-trimethylstannyl 2-adamantyl p-bromobenzenesulfonate in 97% w/w aqueous 2,2,2-trifluoroethanol (97T) at 25 degrees C has been measured (k(H)/k(D) = 1.33). The alpha-kie is abnormally high compared to the value of 1.23 for the corresponding limiting S(N)1 solvolysis of 2-adamantyl p-bromobenzenesulfonate, which proceeds via an extended ion-pair mechanism. A novel mechanism for the solvolysis of the tin compound is proposed that accommodates not only the high alpha-kie but also the absence of internal return.