and neutral conditions with the catalytic TON even higher than that of ruthenium
[84]. Using 0.1 mol% of the manganese pincer complex 3, Michael addition
products of a variety of alcohols and amines with the electrophilic unsaturated
nitriles were synthesized (Table 3).
Based on experimental observations, a plausible mechanism is proposed for the
manganese-catalysed oxa and aza-Michael addition reaction (Scheme 18). Complex
Scheme 18 Proposed mechanism for the manganese-catalysed oxa- and aza-Michael addition
reaction of unsaturated nitriles (X ¼ O or NH)
20
A. Kumar and D. Milstein