Synthesis of Both Enantiomers of a P-Chirogenic 1,2-Bisphospholanoethane Ligand via Convergent Routes and Application to Rhodium-Catalyzed Asymmetric Hydrogenation of CI-1008 (Pregabalin)
摘要:
Both enantiomers of a P-chirogenic 1,2-bisphospholanoethane ligand are synthesized via two convergent methods. The first method relies on the chiral alkylation of 1 -((-)-menthoxy)phospholaneborane using a s-BuLi/(-)-sparteine derived chiral base. Only one enantiomer of the catalyst could be synthesized via this method because only one antipode of sparteine is available in nature. The second route relies on the combination of methylphosphine borane and a chiral 1,4-diol. Either enantiomer of the ligand can be synthesized via the second route from the appropriate enantiomer of the 1,4-diol. Asymmetric hydrogenation using catalyst precursor 36 on acetamidoacrylic acid derivatives provided modest to good enantioselectivity (77-95% ee) under low H-2 pressure (30 psi). Asymmetric hydrogenation of Cl-1008 (pregabalin) precursors, 39 and 40, provided good enantioselectivities (92%) at high catalyst loading (1 mol %) and low pressure (30 psi). Enantiomeric excesses dropped sharply with catalyst loading at this pressure. Increasing the pressure of H-2 caused a significant increase in enantiomeric excess for low catalyst loading reactions. Several studies were undertaken to further investigate the enantioselectivity dependence on both pressure and catalyst loading.
Preparation of P-chirogenic phospholanes and their use in asymmetric synthesis
申请人:Hoge Stewart Garrett
公开号:US20050222464A1
公开(公告)日:2005-10-06
Materials and methods for preparing P-chirogenic monophospholanes and bisphospholanes are disclosed. The methods employ stereoselective cyclization to generate the phospholane rings followed by pyramidal inversion to access a variety of P-chirogenic phospholanes. When bound to transition metals such as rhodium, the disclosed P-chirogenic phospholanes may be used as catalysts in asymmetric synthesis of valuable pharmaceutical chemical entities, including pregabalin.
PREPARATION OF P-CHIROGENIC PHOSPHOLANES AND THEIR USE IN ASYMETRIC SYNTHESIS
申请人:Warner-Lambert Company LLC
公开号:EP1735324A1
公开(公告)日:2006-12-27
US7390931B2
申请人:——
公开号:US7390931B2
公开(公告)日:2008-06-24
[EN] PREPARATION OF P-CHIROGENIC PHOSPHOLANES AND THEIR USE IN ASYMETRIC SYNTHESIS<br/>[FR] PREPARATION DE PHOSPHOLANES P-CHIROGENES ET UTILISATION DE CEUX-CI DANS UNE SYNTHESE ASYMETRIQUE
申请人:WARNER LAMBERT CO
公开号:WO2005095424A1
公开(公告)日:2005-10-13
Materials and methods for preparing P-chirogenic monophospholanes and bisphospholanes are disclosed. The methods employ stereoselective cyclization to generate the phospholane rings followed by pyramidal inversion to access a variety of P-chirogenic phospholanes. When bound to transition metals such as rhodium, the disclosed P-chirogenic phospholanes may be used as catalysts in asymmetric synthesis of valuable pharmaceutical chemical entities, including pregabalin.
Synthesis of Both Enantiomers of a P-Chirogenic 1,2-Bisphospholanoethane Ligand via Convergent Routes and Application to Rhodium-Catalyzed Asymmetric Hydrogenation of CI-1008 (Pregabalin)
作者:Garrett Hoge
DOI:10.1021/ja034715o
日期:2003.8.1
Both enantiomers of a P-chirogenic 1,2-bisphospholanoethane ligand are synthesized via two convergent methods. The first method relies on the chiral alkylation of 1 -((-)-menthoxy)phospholaneborane using a s-BuLi/(-)-sparteine derived chiral base. Only one enantiomer of the catalyst could be synthesized via this method because only one antipode of sparteine is available in nature. The second route relies on the combination of methylphosphine borane and a chiral 1,4-diol. Either enantiomer of the ligand can be synthesized via the second route from the appropriate enantiomer of the 1,4-diol. Asymmetric hydrogenation using catalyst precursor 36 on acetamidoacrylic acid derivatives provided modest to good enantioselectivity (77-95% ee) under low H-2 pressure (30 psi). Asymmetric hydrogenation of Cl-1008 (pregabalin) precursors, 39 and 40, provided good enantioselectivities (92%) at high catalyst loading (1 mol %) and low pressure (30 psi). Enantiomeric excesses dropped sharply with catalyst loading at this pressure. Increasing the pressure of H-2 caused a significant increase in enantiomeric excess for low catalyst loading reactions. Several studies were undertaken to further investigate the enantioselectivity dependence on both pressure and catalyst loading.