Tandem Ireland−Claisen Rearrangement Ring-Closing Alkene Metathesis in the Construction of Bicyclic β-Lactam Carboxylic Esters
作者:Anthony G. M. Barrett、Mahmood Ahmed、Simon P. Baker、Simon P. D. Baugh、D. Christopher Braddock、Panayiotis A. Procopiou、Andrew J. P. White、David J. Williams
DOI:10.1021/jo991932s
日期:2000.6.1
toluenesulfonyl)- and (3S, 4R)-4-(2-propenyl)-3-¿(1R)-1-(tert-butyldimethylsilyloxy)ethyl-++ +azeti din-2-one were converted into beta-lactam dienes via sequential N-alkylation, Ireland-Claisenester enolate rearrangement and esterification. Ring-closing metathesis using the Schrock ¿(CF(3))(2)MeCO(2)Mo(=CHCMe(2)Ph)(=NC(6)H(3)-2,6-iso-Pr(2)) (1) or Grubbs Cl(2)(Cy(3)P)(2)Ru=CHPh (2) carbenes gave a
A recyclable ‘boomerang’ polymer-supported ruthenium catalyst for olefin metathesis
作者:Mahmood Ahmed、Anthony G.M. Barrett、D.Christopher Braddock、Susan M. Cramp、Panayiotis A. Procopiou
DOI:10.1016/s0040-4039(99)01833-x
日期:1999.12
Polymer supported ruthenium catalyst 8 was found to be an effective catalyst for ring closing metathesis. The rate of reaction and activity was found to be comparable to that of homogeneous catalyst 1. In addition, the catalyst could be recycled and re-used up to three times by simple filtration. The residual ruthenium/catalyst content in the product mixtures using catalyst 8 were found to be much reduced