Synthesis of Dihydroxyethylene Isosteres of Dipeptides. 1. Enantiomerically and Diastereomerically Pure 2-Alkyl-5-amino-3-dimethylphenylsilyl-4-octanolides from (S)-N,N-Dibenzylleucinal

All articles of this category 5-Dibenzylamino-3-dimethylphenylsilyl-4-octanolides are prepared via homoenolate addition of ( S )- N,N -dibenzylleucinal [( S )-2-dibenzylamino-4-methylpentanal] and metalated 3-dimethylphenylsilyl-2-propenyl N,N -diisopropylcarbamate, followed by oxidative lactonization. Subsequently, alkyl groups are introduced stereoselectively to the 2-position by means of enolate methodology to yield the title compounds, which are valuable intermediates in the synthesis of dipeptide isosteres.