Enantioselective Ring Opening Reactions

Ligand Cj-Ferriphos Ligand PPF-P Buj Ligand Cg-Ferriphos Ligand C2-Ferriphos 

Additive none Additive none Additive none Additive none 

The relative importance of the planar and central elements of chirality within the Josi-phos skeleton has also been established. Diastereomeric ligands 13 and 22 bear the same R) central chirality but have the opposite planar chirality (Fig. 9.4). Under standard reaction conditions with methanol as the nucleophile, the (R),(S)-ligand 13 gives 100% conversion after approximately 7 min. Conversely, the (i ),(i )-diastereomer 22 gives incom- 

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The enantioselectivity was significantly influenced by the steric factor of the thiols employed. When p-MeC6H4SH and PhSH were used, the optical yields decreased to 69% and 3%, respectively. Shibasaki et al. have reported that gallium-lithium-bi-naphthoxide (GLB) 51 became a good catalyst for the enantioselective ring opening reaction of epoxide for the production of 52 (Eq. 7.39) [46]. 

Schneider, C. (2006) Synthesis of 1,2-difunctionalized fine chemicals through catalytic, enantioselective ring-opening reactions of epoxides., Synthesis, 3919-3944. 

Kureshy, R. I. Singh, S. Khan, N. H. Abdi, S. H. R. Suresh, E. Jasra. R. V. (2006) Facile enantioselective ring-opening reaction of meso-epoxides with anilines using (5)-(-)-BlNOL-Ti complex as a catalyst., Ewr. J. Org. Chem., 1303-1309. 

Transition metal-catalyzed enantioselective ring-opening reactions of oxabicyclic alkenes 03ACR48. 

Scheme 9.23 Enantioselective ring-opening reaction of meso-epoxides using a chiral vanadium complex, reported by Sun and Zhu. ...

Scheme 9.27 Enantioselective ring-opening reaction of racemic epoxide 53b using a chiral niobium complex, reported by Kobayashi. ...

Lautens M, Fagnou K, Hiebert S. Transition metal-catalyzed enantioselective ring-opening reactions of oxabicycUc alkenes. Acc. Chem. Res. 2003 36 48-58. 

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