151764-53-3Relevant articles and documents
4-Isopropyl-2-oxazolin-5-one anion as masked umpoled synthon for both formyl and hydroxycarbonyl anions: Generation, reactivity and synthetic applications
Barco, Achille,Benetti, Simonetta,De Risi, Carmela,Pollini, Gian P.,Spalluto, Giampiero,Zanirato, Vinicio
, p. 4719 - 4734 (2007/10/03)
The anion of the title compound, simply generated in the presence of catalytic amount of triethylamine, reacts with both common electrophilic olefins and aldehydes to give moderate to good yield of Michael or aldol adducts respectively. Mild acid treatment of these adducts at ambient temperature serves to demask the aldehyde function, allowing one to consider the anion of 1 as a nucleophilic acylating equivalent of formaldehyde. On the other hand, the same anion of 1 may act as a masked umpoled synthon for a hydroxycarbonyl anion since its aldol adducts with aldehydes undersent concomitant isomerization and ring cleavage under mild basic conditions producing dipeptides which could be hydrolyzed to give the corresponding carboxylic acids. Synthetic applications of this chemistry in the area of sugar, aminosugar and non-proteinogenic aminoacid derivatives are discussed.
Asymmetric Synthesis of the Taxol and Taxotere C-13 Side Chains
Bunnage, Mark E.,Davies, Stephen G.,Goodwin, Christopher J.
, p. 2385 - 2392 (2007/10/02)
A practical and efficient asymmetric synthesis of the 3-benzoylamino-2-hydroxy-3-phenylpropionic acid derived side chain of the important anticancer agent taxol is described.The pivotal synthetic transformation relies upon the highly diastereoselective tandem lithium amide conjugate addition-electrophilic hydroxylation of tert-butyl cinnamate 4.The resultant anti β-amino-α-hydroxy acid derivative is readily converted to the anti diastereomer of the taxol side chain methyl ester, from which the naturally occuring syn configuration is secured by a simple Mitsunobu inversion sequence via a dihydrooxazole intermediate.Under optimal conditions, this straightforward approach provides the taxol side chain methyl ester (-)-15 (natural enantiomer) in four steps and 60percent yield from tert-butyl cinnamate 4.The protocol is applied to the preparation of all four taxol side chain stereoisomers and is extended to allow for the synthesis of the side chain of taxotere, a potent taxol analogue.
Asymmetric Synthesis of Homochiral syn- and anti-3-Phenylisoserine Derivatives: A Practical Strategy for the Synthesis of the Taxol C-13 Side Chain
Bunnage, Mark E.,Davies, Stephen G.,Goodwin, Christopher J.
, p. 1375 - 1376 (2007/10/02)
A tandem lithium amide conjugate addition-electrophilic hydroxylation approach to the synthesis of N-benzoyl-3-phenylisoserine methyl esters affords a strategy for the practical synthesis of the taxol side chain.
