A novel synthesis of optically active C2-symmetric pyridine derivatives. Efficient reaction of chiral triflates with 2-picolyllithium reagents
摘要:
A variety of optically active CZ-symmetric pyridine derivatives have been prepared from L- or D-tartaric acid as a chiral source via efficient coupling reactions of triflates with 2-picolyllithium reagents, and the utility of 17 and 18 as chiral ligands in the catalytic enantioselective addition of diethylzinc to benzaldehyde has been demonstrated (up to 41% ee). The synthetic procedure for the corresponding meso-isomer was also described.
A novel synthesis of optically active C2-symmetric pyridine derivatives. Efficient reaction of chiral triflates with 2-picolyllithium reagents
摘要:
A variety of optically active CZ-symmetric pyridine derivatives have been prepared from L- or D-tartaric acid as a chiral source via efficient coupling reactions of triflates with 2-picolyllithium reagents, and the utility of 17 and 18 as chiral ligands in the catalytic enantioselective addition of diethylzinc to benzaldehyde has been demonstrated (up to 41% ee). The synthetic procedure for the corresponding meso-isomer was also described.
High purity 2-nitroimidazole derivatives having excellent radiosensitivity and high safety and useful as a drug to be used along with radiotherapy of various cancers can be prepared at a high yield from inexpensive diester of tartaric acid according to the following reaction formua, ##STR1## wherein R.sup.1 and R.sup.2 may be the same or different and each individually represents an aliphatic group or an aromatic group, and X represents a halogen atom.
A variety of optically active CZ-symmetric pyridine derivatives have been prepared from L- or D-tartaric acid as a chiral source via efficient coupling reactions of triflates with 2-picolyllithium reagents, and the utility of 17 and 18 as chiral ligands in the catalytic enantioselective addition of diethylzinc to benzaldehyde has been demonstrated (up to 41% ee). The synthetic procedure for the corresponding meso-isomer was also described.