168297-84-5Relevant articles and documents
Stereoselective gram-scale synthesis of (S)-5,5-dimethyl-4-phenyloxazolidin-2-one
Sugiyama, Shigeo,Arai, Satoshi,Ishii, Keitaro
, p. 149 - 159 (2005)
A stereoselective gram-scale synthesis of (S)-5,5-dimethyl-4-phenyloxazolidin-2-one, SuperQuat [(S)-1], is described. The key step is the diastereoselective reduction of (E)-imine (2), which is synthesized from 2-hydroxy-2-methylpropiophenone (4) and (S)-
Stereoselective functionalisation of SuperQuat enamides: asymmetric synthesis of homochiral 1,2-diols and α-benzyloxy carbonyl compounds
Aciro, Caroline,Davies, Stephen G.,Garner, A. Christopher,Ishii, Yutaka,Key, Min-Suk,Ling, Kenneth B.,Prasad, R. Shyam,Roberts, Paul M.,Rodriguez-Solla, Humberto,O'Leary-Steele, Catherine,Russell, Angela J.,Sanganee, Hitesh J.,Savory, Edward D.,Smith, Andrew D.,Thomson, James E.
, p. 9320 - 9344 (2008/12/22)
Homochiral (E)- and (Z)-enamides derived from SuperQuat (S)-4-phenyl-5,5-dimethyl-oxazolidin-2-one undergo highly diastereoselective epoxidation upon treatment with dimethyldioxirane. Subsequent epoxide opening with meta-chlorobenzoic acid proceeds via a stereoselective SN1-type process, with retention of configuration, to give the corresponding 1′-m-chlorobenzoyl-2′-hydroxy derivatives. Treatment of the SuperQuat enamides with mCPBA effects this two-step transformation in one pot. Reductive cleavage of the isolated 1′-m-chlorobenzoyl-2′-hydroxy derivatives (≥96% de) generates homochiral 1,2-diols in ≥96% ee. Alternatively, regioselective lithiation of the enamide at C(1′) with tBuLi followed by reaction with an aromatic aldehyde and in situ O-benzylation generates a 1′-(benzyloxy-aryl-methyl) substituted enamide with high diastereoselectivity. Subsequent oxidative cleavage of the enamide C{double bond, long}C bond with NaIO4/RuCl3 followed by methanolysis of the resultant N-acyl fragment furnishes an O-benzyl protected α-hydroxy methyl ester in high ee.
SuperQuat N-acyl-5,5-dimethyloxazolidin-2-ones for the asymmetric synthesis of α-alkyl and β-alkyl aldehydes
Bull, Steven D.,Davies, Stephen G.,Nicholson, Rebecca L.,Sanganee, Hitesh J.,Smith, Andrew D.
, p. 2886 - 2899 (2007/10/03)
The proclivity of α-branched N-2′-benzyl-3′-phenylpropionyl derivatives of (S)-4-benzyl-5,5-dimethyl-, (S)-4-phenyl-5,5-dimethyl-, (S)-4-isopropyl-5,5-dimethyl-, (S)-4-benzyl- and (S)-4-benzyl-5,5-diphenyl-oxazolidin-2-ones to generate directly 2-benzyl-3-phenylpropionaldehyde upon hydride reduction with DIBAL is investigated. The (S)-4-benzyl-5,5-dimethyl-derivative proved optimal for inhibition of endocyclic nucleophilic attack, giving 2-benzyl-3-phenylpropionaldehyde in good yield upon reduction. Application of this methodology for the asymmetric synthesis of chiral aldehydes via diastereoselective enolate alkylation of a range of (S)-N-acyl-4-benzyl-5,5-dimethyloxazolidin-2-ones to afford an array of α-substituted-N-acyl-5,5-dimethyloxazolidin-2-ones (85-94% de) and subsequent reduction with DIBAL afforded directly non-racemic α-substituted aldehydes without loss of stereochemical integrity (87-94% ee). The extension of this protocol for the asymmetric synthesis of β-substituted aldehydes is demonstrated, via the diastereoselective conjugate addition of a range of organocuprates to (S)-N-acyl-4-phenyl-5,5-dimethyloxazolidin-2-ones which proceeds with high diastereoselectivity (generally >95% de). Reduction of the conjugate addition products with DIBAL gives non-racemic β-substituted aldehydes in high yields and in high ee (generally >95% ee). This methodology is exemplified by the asymmetric synthesis of (R)-3-isopropenylhept-6-enal, which has previously been used in the synthesis of (3Z,6R)-3-methyl-6-isopropenyl-3,9-decadien-1-yl acetate, a component of the sex pheromones of the California red scale.