1,2-Asymmetric induction in the radical addition of organotin hydrides to (−)-menthyl( E)-2,3-disubstituted propenoates

• Published in: Journal of organometallic chemistry Vol. 555; no. 2; pp. 151 - 159
• Main Authors: Mandolesi, S.D, Koll, L.C, Chopa, A.B, Podestá, J.C
• Format: Journal Article
• Language: English
• Published: LAUSANNE Elsevier B.V 30.03.1998; Elsevier
• Subjects: (−)-Menthyl( E)-2,3-disubstituted propenoates; 1,2-Asymmetric induction; Chemistry; Chemistry, Inorganic & Nuclear; Chemistry, Organic; Organotin hydrides; Physical Sciences; Science & Technology; 1,2-Asymmetric induction; Organotin hydrides; (−)-Menthyl( E)-2,3-disubstituted propenoates; HYDROSTANNATION; GERMANIUM; 1,2-asymmetric induction; SILICON; TIN; ELECTRON-SPIN RESONANCE; organotin hydrides; (-)-menthyl(E)-2,3-disubstituted propenoates; CHLOROHYDRIDE
• ISSN: 0022-328X; 1872-8561
• DOI: 10.1016/S0022-328X(97)00637-2

The results obtained in the free radical hydrostannation of (−)-menthyl( E)-2,3-diphenylpropenoate ( 1) with tri- n-butyl- and triphenyltin hydride, and of (−)-menthyl( E)-2-phenyl-2-butenoate ( 7) with trimethyltin hydride are reported. The absolute configuration of the new organotin adducts was determined by combining 1H- and 13C-NMR data with chemical correlation. The additions took place in all cases following a syn stereochemistry that led to diastereomeric excesses ranging between 73 and 100%. The observed stereochemistry is explained, taking into account both the allylic strain and the hyperconjugation with β-trialkyltin substituent existing in the intermediate radicals. Full 1H-, 13C- and 19Sn-NMR data are given.