کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
69291 | 48535 | 2006 | 8 صفحه PDF | دانلود رایگان |

A comparative study of the ligand (5–10) effect on the rhodium catalytic activity and selectivity in the homogeneous hydrogenation of α,β-unsaturated oxosteroids (1–4) is reported. The highest activity for CC reduction was observed with phosphite ligands, being diphosphite 10 the most active. Furthermore, the presence of phosphite 6 significantly enhances the chemo and α-diastereoselectivity for the hydrogenation reaction. The β-methyl groups of the steroidal framework lead to a very high α-diastereoselectivity, even in the absence of phosphorous ligands. Substrate 4 is the paradigm presenting higher than 94% α-diastereoselectivity for any catalytic system studied.The catalytic system formed from rhodium and the new diphosphite 10 also revealed a remarkable tendency for the CO reduction and a noteworthy stability.
Figure optionsDownload as PowerPoint slide
Journal: Journal of Molecular Catalysis A: Chemical - Volume 247, Issues 1–2, 16 March 2006, Pages 275–282