Catalysis of Organic..

Robitaille, Clément, Chapuzet and Lessard 285NO 2NO 2NH 2NO 2NH 2NH 214 15 16CCH (pH 12.5) 100%ECH (pH 12.5) < 1%7%ECH (pH 13) (9) 90% n.dScheme 5derivative 16 was detected. The ECH under the same conditions (0.05 M KOH) gavevery poor results as shown in Scheme 5. However, ECH in a neutral medium (acetatebuffer) in MeOH-H 2 O (93:7 v/v)) has been reported to be 100% selective givingnitroamine 15 as the sole product in a 100% yield (9).Nitroalkyl groupsThe CCH of nitroacetylenic acetal 17 gave the corresponding amine 18 in a lowyield (23%) (Scheme 6). The reduction stopped at the hydroxylamine whichunderwent decomposition to acetylenic alcohol 19 (11%) and an ene-yne acetalwhich was further reduced to diene acetal 20 (67%). The ECH in neutral medium(acetate buffer in CH 3 OH-H 2 O 93:7 v/v) has been reported to give 72% of acelylenicamine 18 (3, 10). The products resulting from the decomposition of the intermediateacetylenic hydroxylamine were not identified (3, 10).NO 2OEtNH 2OEtOHOEtOEtOEtOEtOEt17 18 19 20OEtCCH (pH 12.5) 23% 11% 67%ECH (pH 7) (3, 8) 72% - -Scheme 6The CCH of p-cyano-nitrocumene (21) under the standard conditions gave p-cyano-aminocumene (22) as the main product (84%) (Scheme 7), the alcohol 23(14%) and the styrene 24 (5%) both resulting from the decomposition of theintermediate hydroxylamine. The ECH under the same conditions is much lessselective giving only 26% of p-cyano-aminocumene (22) together with alcohol 23(36%, the main product), the styrene 24 (17%), p-cyanocumene (25) (8%), and p,p’-dicyanobicumyl (26) (18%) (Scheme 7). The ECH in neutral medium (pH 5, NaCl0.1 M in methanol-water 95:5 (v/v)) has been reported to be highly selective giving91% of isolated p-cyano-aminocumene (22) (1, 3). The bicumyl 26 results from elec-