| 摘要 |
<p>A process for the preparation of alpha-6-deoxytetracyclines from the corresponding 6-methylene tetracyclines is described using a silica-supported heterogeneous rhodium catalyst of general formula (I), wherein R and R' are each selected from hydrogen and C1-C4 alkyl; x is an integer from 1 to 6; Ph is phenyl; y is an integer from 1 to 3; and L is a ligand selected from alkoxysilyl-substituted alkyldiphenyl phosphines. The process stereospecifically produces the alpha epimers at higher yields while using lower rhodium metal levels than prior methods.</p> |
