Stereoselective Radical Tandem Cyclohydrostannation of Optically Active Di-unsaturated Esters of TADDOL

D. C. GERBINO; L. C. KOLL; S. D. MANDOLESI; J. C. PODESTÁ

ORGANOMETALLICS

American Chemical Society

Lugar: Columbia, OH, 43210, USA ; Año: 2008 vol. 27 p. 660 - 665

0276-7333

This paper reports the results obtained in a study on the radical addition of triorganotin hydrides, R3SnH (R = Me, n-Bu, Ph; Neophyl), to four TADDOL unsaturated diesters. It was found that these reactions lead in high yields to products of cyclohydrostannation instead of the expected products of double addition. It was also found that whereas the addition of these hydrides to TADDOL diacrylate and TADDOL dimethacrylate leads to the expected mixtures of two and four cyclodecane diastereoisomers respectively, the addition of triphenyltin hydride to TADDOL disubstituted acrylates yields only four out of the sixteen possible stereoisomers. The observed high stereoselectivity is consistent with the radical tandem cyclohydrostannation mechanism proposed. Only in the case of the hydrostannation of TADDOL diacrylate with trimethyl- and triphenyltin hydrides it was possible the separation of the diastereoisomers obtained in higher proportion (5a and 8a) from the mixtures of crude products. Cycloundecane esters 5a and 8a were reduced with lithium aluminum hydride leading to the corresponding optically active diols 26 and 27 in high yield. Full 1H, 13C, and 119Sn NMR data are given. corresponding optically active diols 26 and 27 in high yield. Full 1H, 13C, and 119Sn NMR data are given. corresponding optically active diols 26 and 27 in high yield. Full 1H, 13C, and 119Sn NMR data are given. products. Cycloundecane esters 5a and 8a were reduced with lithium aluminum hydride leading to the corresponding optically active diols 26 and 27 in high yield. Full 1H, 13C, and 119Sn NMR data are given. corresponding optically active diols 26 and 27 in high yield. Full 1H, 13C, and 119Sn NMR data are given. corresponding optically active diols 26 and 27 in high yield. Full 1H, 13C, and 119Sn NMR data are given. products. Cycloundecane esters 5a and 8a were reduced with lithium aluminum hydride leading to the corresponding optically active diols 26 and 27 in high yield. Full 1H, 13C, and 119Sn NMR data are given. corresponding optically active diols 26 and 27 in high yield. Full 1H, 13C, and 119Sn NMR data are given. corresponding optically active diols 26 and 27 in high yield. Full 1H, 13C, and 119Sn NMR data are given. these reactions lead in high yields to products of cyclohydrostannation instead of the expected products of double addition. It was also found that whereas the addition of these hydrides to TADDOL diacrylate and TADDOL dimethacrylate leads to the expected mixtures of two and four cyclodecane diastereoisomers respectively, the addition of triphenyltin hydride to TADDOL disubstituted acrylates yields only four out of the sixteen possible stereoisomers. The observed high stereoselectivity is consistent with the radical tandem cyclohydrostannation mechanism proposed. Only in the case of the hydrostannation of TADDOL diacrylate with trimethyl- and triphenyltin hydrides it was possible the separation of the diastereoisomers obtained in higher proportion (5a and 8a) from the mixtures of crude products. Cycloundecane esters 5a and 8a were reduced with lithium aluminum hydride leading to the corresponding optically active diols 26 and 27 in high yield. Full 1H, 13C, and 119Sn NMR data are given. corresponding optically active diols 26 and 27 in high yield. Full 1H, 13C, and 119Sn NMR data are given. corresponding optically active diols 26 and 27 in high yield. Full 1H, 13C, and 119Sn NMR data are given. products. Cycloundecane esters 5a and 8a were reduced with lithium aluminum hydride leading to the corresponding optically active diols 26 and 27 in high yield. Full 1H, 13C, and 119Sn NMR data are given. corresponding optically active diols 26 and 27 in high yield. Full 1H, 13C, and 119Sn NMR data are given. corresponding optically active diols 26 and 27 in high yield. Full 1H, 13C, and 119Sn NMR data are given. products. Cycloundecane esters 5a and 8a were reduced with lithium aluminum hydride leading to the corresponding optically active diols 26 and 27 in high yield. Full 1H, 13C, and 119Sn NMR data are given. corresponding optically active diols 26 and 27 in high yield. Full 1H, 13C, and 119Sn NMR data are given. corresponding optically active diols 26 and 27 in high yield. Full 1H, 13C, and 119Sn NMR data are given. these reactions lead in high yields to products of cyclohydrostannation instead of the expected products of double addition. It was also found that whereas the addition of these hydrides to TADDOL diacrylate and TADDOL dimethacrylate leads to the expected mixtures of two and four cyclodecane diastereoisomers respectively, the addition of triphenyltin hydride to TADDOL disubstituted acrylates yields only four out of the sixteen possible stereoisomers. The observed high stereoselectivity is consistent with the radical tandem cyclohydrostannation mechanism proposed. Only in the case of the hydrostannation of TADDOL diacrylate with trimethyl- and triphenyltin hydrides it was possible the separation of the diastereoisomers obtained in higher proportion (5a and 8a) from the mixtures of crude products. Cycloundecane esters 5a and 8a were reduced with lithium aluminum hydride leading to the corresponding optically active diols 26 and 27 in high yield. Full 1H, 13C, and 119Sn NMR data are given. corresponding optically active diols 26 and 27 in high yield. Full 1H, 13C, and 119Sn NMR data are given. corresponding optically active diols 26 and 27 in high yield. Full 1H, 13C, and 119Sn NMR data are given. products. Cycloundecane esters 5a and 8a were reduced with lithium aluminum hydride leading to the corresponding optically active diols 26 and 27 in high yield. Full 1H, 13C, and 119Sn NMR data are given. corresponding optically active diols 26 and 27 in high yield. Full 1H, 13C, and 119Sn NMR data are given. corresponding optically active diols 26 and 27 in high yield. Full 1H, 13C, and 119Sn NMR data are given. products. Cycloundecane esters 5a and 8a were reduced with lithium aluminum hydride leading to the corresponding optically active diols 26 and 27 in high yield. Full 1H, 13C, and 119Sn NMR data are given. corresponding optically active diols 26 and 27 in high yield. Full 1H, 13C, and 119Sn NMR data are given. corresponding optically active diols 26 and 27 in high yield. Full 1H, 13C, and 119Sn NMR data are given. 3SnH (R = Me, n-Bu, Ph; Neophyl), to four TADDOL unsaturated diesters. It was found that these reactions lead in high yields to products of cyclohydrostannation instead of the expected products of double addition. It was also found that whereas the addition of these hydrides to TADDOL diacrylate and TADDOL dimethacrylate leads to the expected mixtures of two and four cyclodecane diastereoisomers respectively, the addition of triphenyltin hydride to TADDOL disubstituted acrylates yields only four out of the sixteen possible stereoisomers. The observed high stereoselectivity is consistent with the radical tandem cyclohydrostannation mechanism proposed. Only in the case of the hydrostannation of TADDOL diacrylate with trimethyl- and triphenyltin hydrides it was possible the separation of the diastereoisomers obtained in higher proportion (5a and 8a) from the mixtures of crude products. Cycloundecane esters 5a and 8a were reduced with lithium aluminum hydride leading to the corresponding optically active diols 26 and 27 in high yield. Full 1H, 13C, and 119Sn NMR data are given. corresponding optically active diols 26 and 27 in high yield. Full 1H, 13C, and 119Sn NMR data are given. corresponding optically active diols 26 and 27 in high yield. Full 1H, 13C, and 119Sn NMR data are given. products. Cycloundecane esters 5a and 8a were reduced with lithium aluminum hydride leading to the corresponding optically active diols 26 and 27 in high yield. Full 1H, 13C, and 119Sn NMR data are given. corresponding optically active diols 26 and 27 in high yield. Full 1H, 13C, and 119Sn NMR data are given. corresponding optically active diols 26 and 27 in high yield. Full 1H, 13C, and 119Sn NMR data are given. products. Cycloundecane esters 5a and 8a were reduced with lithium aluminum hydride leading to the corresponding optically active diols 26 and 27 in high yield. Full 1H, 13C, and 119Sn NMR data are given. corresponding optically active diols 26 and 27 in high yield. Full 1H, 13C, and 119Sn NMR data are given. corresponding optically active diols 26 and 27 in high yield. Full 1H, 13C, and 119Sn NMR data are given. 5a and 8a) from the mixtures of crude products. Cycloundecane esters 5a and 8a were reduced with lithium aluminum hydride leading to the corresponding optically active diols 26 and 27 in high yield. Full 1H, 13C, and 119Sn NMR data are given. corresponding optically active diols 26 and 27 in high yield. Full 1H, 13C, and 119Sn NMR data are given. corresponding optically active diols 26 and 27 in high yield. Full 1H, 13C, and 119Sn NMR data are given. 5a and 8a were reduced with lithium aluminum hydride leading to the corresponding optically active diols 26 and 27 in high yield. Full 1H, 13C, and 119Sn NMR data are given.26 and 27 in high yield. Full 1H, 13C, and 119Sn NMR data are given.