Tandem Conjugate Additions and 3-Aza-Cope Rearrangements of Tertiary Allyl Amines and Cyclic α-Vinylamines with Acetylenic Sulfones. Applications to Simple and Iterative Ring Expansions Leading to Medium and Large-Ring Nitrogen Heterocycles
作者:Mitchell H. Weston、Katsumasa Nakajima、Thomas G. Back
DOI:10.1021/jo800600a
日期:2008.6.1
Tertiary acyclic allyl amines and tertiary cyclic α-vinyl amines undergo conjugate additions to acetylenic sulfones to produce zwitterion intermediates, followed by 3-aza-Cope rearrangements. In the case of cyclic α-vinyl amines, the process results in ring-expansion, providing a novel route to 9- to 17-membered cyclic amines. The Hammett plot for the reaction of 8b with 2a−2f shows ρ = +1.19, which
Ring-expansion of tertiary cyclic α-vinylamines by tandem conjugate addition to (p-toluenesulfonyl)ethyne and formal 3-aza-Cope rearrangement
作者:Mitchell H. Weston、Katsumasa Nakajima、Masood Parvez、Thomas G. Back
DOI:10.1039/b607713g
日期:——
A novel ring-expansion protocol is based on the conjugate additions of cyclic alpha-vinylamines to (p-toluenesulfonyl)ethyne, followed by aza-Cope rearrangements of the resulting zwitterions, to afford medium and large-ring cyclic amines under remarkably mild conditions.