Cyclizations wherein an epoxide acts as the source of initiation and termination steps. Evidence for an early transition state in biomimetic epoxide cyclizations
作者:Stephen K. Taylor、Scott A. May、Jeffrey A. Hopkins
DOI:10.1016/s0040-4039(00)91775-1
日期:1993.2
Epoxides which can competitively cyclize to either a double bond or aromatic group undergo novel bicyclizations where an epoxide is the source of initiating and terminating groups. The results suggest that biomimetic epoxidecyclizations involve early transition states.
Substituent Effects On Intramolecular Epoxide Cyclizations That Can Competitively Occur at Aromatic or Double Bond Positions<sup>1</sup>
作者:Stephen K. Taylor、Scott A. May、Eric S. Stansby
DOI:10.1021/jo951945f
日期:1996.1.1
The effects of substituents on epoxides that can competitively cyclize at either a double bond or aromatic position were determined. Adding a group that would stabilize the transition state of the double bond cyclization of an epoxide that underwent predominantly aromatic cyclization increased the relative amount of the former pathway, but not dramatically. Adding a strong activating substituent to the aromatic group of an epoxide that underwent predominantly double bond cyclization increased the relative amount of aromatic cyclization, but a complex product mixture was obtained. An explanation of the behavior observed is presented.