Reactivity of chiral alpha-amidoalkylphenyl sulfones with stabilized carbanions. stereoselective synthesis of optically active 1-aminopyrrolizidine.
Metal enolates and functionalized allylzinc reagents react with optically active alpha-amidoalkylphenyl sulfones to give N-carbamoylamino derivatives with variable levels of anti diastereoselectivity. Zinc enolates provide comparable results with respect to lithium enolates in terms of diastereoselectivity but afford beta-amino ester derivatives in lower yield. The synthetic utility of the obtained chiral N-carbamoylamino esters is demonstrated by the first enantioselective synthesis of (-)-1-aminopyrrolizidine a central intermediate for the preparation of various biologically active substances.
Giri
Nicola
N
Dipartimento di Scienze Chimiche, Università di Camerino, via S. Agostino, 1, I-62032 Camerino, Italy.
Petrini
Marino
M
Profeta
Roberto
R
D000838:Anions / Q000737:chemistry*; D002244:Carbon / Q000737:chemistry*; D008968:Molecular Conformation; D011763:Pyrrolizidine Alkaloids / Q000138:chemical synthesis*; D013237:Stereoisomerism; D013450:Sulfones / Q000737:chemistry*
C494067:1-aminopyrrolizidine; D000838:Anions; D011763:Pyrrolizidine Alkaloids; D013450:Sulfones; D002244:Carbon