Branko Dikic

Asymmetric Synthesis of Chiral Cyclic Amino Acids by Diels-Alder Reactions of (2S)- and (2R)-4-Methyleneoxazolidin-5-ones

The synthesis of chiral (2S)- and (2R)-4-methyleneoxazolidin-5-ones, in high enantiomeric purity from (S)-S- methylcysteine, and their highly exo-selective Diels -Alder reactions with cyclic dienes are described. (1R,2S,4S)-2-Aminobicyclo[2.2.1]heptane-2-carboxylic acid has been prepared in 92% e.e. by these methods. A number of the products have been characterized by single-crystal X-ray methods, and their structure systematics examined.

Diastereoselective additions of lithiated N-tertbutyldiphenylsilyl- S-methyl-S-phenylsulfoximine to imines and aldehydes☆

Abstract Lithiated N-tert-butyldiphenylsilyl-S-methyl-S-phenylsulfoximine undergoes 1,2 addition to imines (R 1 CHNPh) and aldehydes (RCHO) to give diastereomeric adducts. The diastereoselection of the former reactions is dependent on the steric demand of the imine substituent R 1 , while that of the latter is independent of the steric demand of the aldehyde substituent R.

Highly exo-diastereoselective Diels–Alder reactions of (2S)-N-benzoyl-2-tert-butyl-4-methylene-1,3-oxazolidin-5-one

(2S)-N-Benzoyl-2-tert-butyl-4-methylene-1,3-oxazolidin-5-one undergoes highly exo-diastereoselective Diels–Alder reactions with cyclopentadiene and cyclohexa-1,3-diene.

Diastereoselective kinetically and thermodynamically controlled additions of (R)-(+)-methyl p-tolyl sulphoxide anion to imines (tolyl = C6H4Me)

The anion of (R)-(+)-methyl p-tolyl sulphoxide reacts diastereoselectively with imines to give chiral β-amino sulphoxides.

Diastereoselective additions of lithiated N-t-butyldiphenylsilyl-S-benzyl-S-methylsulphoximine to imines

Lithiated N-t-butyldiphenylsilyl-S-methylsulphoximine undergoes highly diastereoselective, 1,2-addition to imines to give adducts with the 1S*, 2S*, S*s relative stereochemistry.