Tandem conjugate addition-α-alkylation of unsaturated amides. Synthetic methodology.

1,4-Addition of RLi, RMgX, and (RS) ₂CHLi reagents to unsaturated amides 2a-c followed by α-alkylation is shown to constitute a general and efficient synthetic procedure for the formation of two CC bonds in a single step.     

Allenes-41 : The addition of thiols to allenyl- and phenylpropynyl- nitrile and the formation of thiazolines and benzothiazoles

Thiols add to allenylnitriles to give unconjugated nitriles which may be isomerised to conjugated enesulphide nitriles either at high temperature (200°) or with base. Phenylpropynenitrile gives conjugated adducts directly. Heating the conjugated adducts from aminoethanethiols at > 200° results in 5-exotrig ring closure and elimination of acetonitrile to give thiazolines and benzothiazoles.     

Tandem conjugate addition-α-alkylation of unsaturated amides. Synthesis of 1-aryltetralin lignans

The amide alcohols, obtained in one step from the sequential reaction of N,N-dimethylcrotonamide with dithiane anion and aryl aldehyde, were efficiently converted into the lignans galcatin and isogalcatin.