Method of preparing stereospecific nitroaldols

Details Method of preparing stereospecific nitroaldols Method of preparing stereospecific nitroaldols

1988-08-05

1990-06-12

Lone, Warren B.

Organic compounds -- part of the class 532-570 series

Organic compounds

Oxygen containing

568704, C07C 7922

Patent

active

049335057

ABSTRACT:
A method of controlling the diastereoselectivity of the nitroaldol reaction by the use of titanium, zirconium and aluminum based Lewis acids is disclosed. In a preferred embodiment, the reaction of lithium nitronate anion with aldehydes in THF/CH.sub.2 Cl.sub.2 at reduced temperature in the presence of isopropoxy titanium trichloride (TiCl.sub.3 (OPr.sup.i)) yields nitro alcohols enriched in the erythro diastereomer. Erythro-threo ratios of 11.2:1-3.4:1 for aromatic aldehydes and 3.8:1-1:1 for aliphatic aldehydes are typically obtained.

REFERENCES:
patent: 2132353 (1938-10-01), Hass
patent: 2475996 (1946-07-01), Smith
patent: 2543957 (1951-03-01), Crooks et al.
patent: 3005854 (1961-10-01), Braun et al.
patent: 3660500 (1972-05-01), Hardtman et al.
Seebach, et al., Helv. Chim. Acta, 65:1101 (1982).
Seebach, et al., J. Am. Chem. Soc., 107:3601 (1985).
Hanessian et al., Tetrahedon Lett., 16:1261 (1985).
Bordwell and Arnold, "The Stereochemistry of the Hydrogenation of cis-and trans-1-Nitro-2-phenylcyclohexane Using W-2 Raney Nickel Catalyst ", vol. 27, 4426-4428, Dec., 1962.
Bordwell and Garbish, Jr., "Nitrations with Acetyl Nitrate. IV.", vol. 28, 1765-1769, July, 1963.
Sundberg and Bukowick, J. Org. Chem., 33:4098-4102 (1968).
Bordwell and Birankowski, "Nitrations with Acetyl Nitrate. V.", vol. 32, 629-634 (1967).
Barrett, Grabowski, Russell, J. Org. Chem., 51:1012-1015 (1986).
Nielsen, "The Isomeric Dinitrocyclohexanes. II. Stereochemistry", vol. 27, 1998-2001 (1962).
Reetz and Peter, Tetrahedon Lett., 22:4691-4694 (1981).

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