A highly stereoselective trichlorosilane-mediated reduction of N-benzyl enamines was developed; the combination of a low cost, easy to make metal-free catalyst and an inexpensive chiral auxiliary allowed to perform the reaction on substrates with different structural features often with total control of the stereoselectivity. By easy deprotection through hydrogenolysis followed by conversion of β-aminoester
METHOD FOR PRODUCING AN OPTICALLY ACTIVE TETRAHYDROQUINOLINE
申请人:Moroi Takashi
公开号:US20100036149A1
公开(公告)日:2010-02-11
The present invention provides an industrially advantageous production method of optically active tetrahydroquinolines of formula (1),
which comprises:
1) a step of reacting a β-ketoester of formula (2)
with an amine of formula (3)
to produce an enaminoester of formula (4);
2) a step of subjecting the enaminoester of formula (4) above obtained in 1) to asymmetric hydrogenation to produce an optically active β-amino acid derivative of formula (5);
3) a step of amidating the optically active β-amino acid derivative (5) above obtained in 2) to produce an amide of formula (6);
4) a step of alkoxycarbonylating the amide of formula (6) above obtained in 3) to produce a compound of formula (7);
and
5) a step of subjecting the compound of formula (7) above to cyclization to produce the optically active tetrahydroquinoline of formula (1).
years with excellent results. Several chiral organocatalysts and even enzymes have proved to be resistant to milling conditions, which allows for rather efficient enantioselective transformations under ball-milling conditions. The present article reports the first example of a liquid-assisted grinding (LAG) mechanochemical enzymaticresolution of racemic β3-amino esters employing Candida antarctica lipase