Reduction by tributyltin hydride of carbonyl compounds adsorbed on silica gel: selective reduction of aldehydes

Synthesis, Chromatographic Resolution, and Anti-Human Immunodeficiency Virus Activity of (±)-Calanolide A and Its Enantiomers

“…For example, NaBH 4 /CeCl 3 , NaBH 4 /CuCl 2 , Baker's yeast, L-Selectride, and DIBAL preferentially reacted at the lactone position to lead to the formation of diol 13 as the major product. In contrast, n -Bu 3 SnH produced chromene ring-opened compound 14 in a 15% yield and a mixture which contained unsaturated alcohol 15 , as indicated by 1 H NMR spectroscopy. The use of SmI 2 /HMPA and 9-BBN resulted in a similar mixture to that produced by n -Bu 3 SnH, while [(Ph 3 P)CuH] 6 did not react with chromone 12 .…”

“…mp 130-132 °C):1 H NMR (300 MHz, CDCl3) δ 1.05 (3H, t, J ) 7.3 Hz, CH3), 1.22 (3H, d, J ) 6.9 Hz, CH3), 1.56 (3H, d, J ) 6.3 Hz, CH3), 1 54. and 1.57 (6H, 2 s, 2 CH3), 1.63 (2H, apparent sextet, J ) 7.6 Hz, CH2), 2.57 (1H, dq, J ) 6.9, 11.0 Hz, H-11), 2.91 (2H, t, J ) 7.6 Hz, CH2), 4.33 (1H, dq, J ) 6.3, 11.1 Hz, H-10), 5.64 (1H, d, J ) 10.1 Hz, H-7), 6.05 (1H, s, H-3), 6.66 (1H, d, J ) 10.1 Hz, H-8); MS (CI) 369 (100, M + 1); IR 1736 (vs, CdO), 1686 (s, CdC-CdO), 1645 (m), 1606 (m), 1578 (s), 1557 (vs) cm -1 .…”

An immobilized organotin catalyst for reduction of ketones and aldehydes

“…Tributyltin hydride adsorbed on silica has also been examined for the selective reduction of aldehydes. 3 Organotin alkoxides are known to function as efficient catalysts for the transfer of hydrogen from silicon hydrides to organic substrates such as carbonyl compounds4 and are comparable in their range of applications to the stoicheiometric organotin hydride reagents,s which continue to find important applications in organic synthesis. 6 We have prepared an organotin compound linked to the surface of silica and have developed a convenient, immobilized version of this homogeneous reducing system.…”

Ambient-Pressure and Base-Free Aldehyde Hydrogenation Catalyst Supported by a Bifunctional Abnormal NHC Ligand

“…Aldehyde-to-alcohol is a fundamental organic transformation utilized on a regular basis not only in academic laboratories but also in industry for the synthesis of various fine and bulk chemicals . To realize such a transformation, environmentally unfriendly traditional reduction with NaBH 4 , boranes, LiAlH­(OR) 3 , or Bu 3 SnH is still employed, leading to a large amount of undesirable waste . This problem necessitated development of a catalytic aldehyde hydrogenation (CAH) protocol using H 2 gas as a clean and green reagent .…”