Asymmetric catalysis based on chiral phospholanes and hydroxyl phospholanes
申请人:The Penn State Research Foundation
公开号:US06727377B2
公开(公告)日:2004-04-27
Chiral phosphine ligands derived from chiral natural products including D-mannitol and tartaric acid. The ligands contain one or more 5-membered phospholane rings with multiple chiral centers, and provide high stereoselectivity in asymmetric reactions.
The C2-symmetric buildingblock 1,2:5,6-di-N,O-carbonyl-1,6-diamino-3,4-O-isopropylidene-d-mannitol can be synthesized from d-mannitol in four steps using a nucleophilic substitution with cyanate and a subsequent cyclization in the final key step. The direct electrochemical oxidation of the resulting dioxazolidinone at 40 mA/cm2 in methanol at graphite electrodes with sodium benzene sulfonate as supporting
的c ^ 2 -对称积木1,2:5,6-二- ñ,ö羰基-1,6-二氨基-3,4- ö异亚丙基d甘露醇可以从d-甘露醇在四个步骤来合成在最后的关键步骤中,用氰酸酯进行亲核取代,然后进行环化。在石墨电极上用苯磺酸钠作为支持电解质,在甲醇中在甲醇中以40 mA / cm 2的浓度对二恶唑烷酮进行直接电化学氧化,生成二甲氧基化产物,该产物可用于各种非对映选择性的酰胺基烷基化反应。在所有情况下,观察到双反立体选择性。
Highly Flexible Synthetic Routes to Functionalized Phospholanes from Carbohydrates
作者:Yuan-Yong Yan、T. V. RajanBabu
DOI:10.1021/jo991762j
日期:2000.2.1
Highly functionalized phospholanes 15, 17, and 26 and the corresponding diastereomers in which the configurations of the phospholane carbon-2 and carbon-5 are inverted can be readily prepared from d-mannitol by displacement of the appropriate dimesylate or cyclic sulfate with dilithiumphosphide reagents. The diols from which these ligands are prepared can also be converted into diarylphosphinite ligands
Aspyrone (1) was elaborated in an optically pure form by a key reaction involving the highly diastereoselective addition of tetrahydropyranone enol ate to 2-tosyloxy-aldehyde and the subsequent in situ formation of an epoxide.
A chiral hydroxyl bisphospholane, 1,2-bis[(2S,3S,4S,5S)-3,4-dihydroxyl-2,5-dimethylphospholanyl]benzene (4), was synthesized from readily available d-mannitol. Its Rh(I) complex catalyzes asymmetric hydrogenation of dehydroaminoacids and their ester derivatives with excellent enantioselectivities (98 to >99% ee).