The addition of aromatic amines to terminal acetylenes in the presence of catalytic amounts of mercury(l1) chloride gives imines, enamines, and 1,2,3,4-tetrahydroquinoIine derivatives; mercury(l1) acetate shows considerably less catalytic activity and may be used for the non-catalytic preparation of imines, enamines, NN'-disubstituted acetamidines, and NN-disubstituted acetamides.

[reaction: see text] Enantiopure (1R,2S)-1-benzyl- and 1-arylaziridine-2-carboxamides were obtained by kinetic resolution of their racemates by Rhodococcus rhodochrous IFO 15564 catalyzed hydrolysis. Several regio- and enantioselective nucleophilic ring openings of (1R,2S)-1-benzylaziridine-2-carboxamide or its LAH-reduced product led to a series of enantiopure products, such as O-methyl-l-serine and some vicinal diamines.

No abstract

No abstract

Lipase B from Candida antarctica (CAL-B) catalyses the highly enantioselective (E > 200) transesterification of some 1-biaryl-2-yl-, -3-yl-, and -4-ylethanols and -propan-1-ols, as well as 1-(o-, m-, and p-pyridylphenyl)ethanols, 6, with vinyl acetate, Kazlauskas rule being obeyed in all cases. meta and para-Substituted substrates were transformed within several hours (conversion degree ranging from 23 -50%), reaction rates for propan-1-ol derivatives being slower than those for ethanol derivatives. Transesterifications of ortho-substituted alcohols took several days and were accompanied by a chemoenzymatic side reaction: the formation of another acetate derived from the hemiacetal between 6 and acetaldehyde coming from vinyl acetate. This side reaction was suppressed in the presence of isopropenyl acetate as acyl donor, conversion degrees for transesterification ranging from 20 -40% after ten days (E > 200). The usefulness of (R)-6p as ligand in the asymmetric addition of diethylzinc to benzaldehyde was also demonstrated.