Organic base effects in NHC promoted O- to C-carboxyl transfer; chemoselectivity profiles, mechanistic studies and domino catalysis
作者:Craig D. Campbell、Christopher J. Collett、Jennifer E. Thomson、Alexandra M. Z. Slawin、Andrew D. Smith
DOI:10.1039/c1ob05160a
日期:——
The O- to C-carboxyltransfer of oxazolylcarbonates promoted by triazolinylidenes, generated in situ with NEt3, shows a markedly different rate and chemoselectivity profile to the same reaction promoted by triazolinylidenes generated using KHMDS. The mechanism of these pathways has been probed through extensive crossover studies to understand this process. The use of NEt3 as a base allows domino multi-step
Tandem multi-step synthesis of C-carboxyazlactones promoted by N-heterocyclic carbenes
作者:Craig D. Campbell、Nicolas Duguet、Katherine A. Gallagher、Jennifer E. Thomson、Anita G. Lindsay、AnnMarie C. O’Donoghue、Andrew D. Smith
DOI:10.1039/b806816j
日期:——
Cascade reaction sequences incorporating N-heterocyclic carbene-based organocatalysis have been developed that allow the direct preparation of a range of (±)-4-phenoxycarbonylazlactones in good isolated yields (66–84%) from the corresponding N-p-anisoyl amino acids.