Reactions of Carbonyl Compounds with Other Carbon Nucleophiles

Reactions of Carbonyl Compounds with Other Carbon Nucleophiles 

The Ni-catalyzed olefination of aromatic aldehydes and cinnamaldehyde with alkylzinc reagents proceeds smoothly in the presence of MesSiCl [118]. Unlike the Wittig reaction, this reaction achieves high E selectivity. A plausible mechanism consists of three steps the Zn-Ni transmetalation between an alkylzinc and the nickel catalyst, the MesSiCl-mediated addition of the resultant alkylnickel 

The importance of Lewis acid catalysis in the Diels-Alder reactions is well recognized. MeaSiOTf (la), which is a most versatile silicon Lewis acid catalyst, is effective in the Diels-Alder reaction of activated 1,3-dienes, while it cannot catalyze the reaction of simple 1,3-dienes [8, 9]. However, the recent developments of stronger silicon Lewis acids overcome the limitation. 

A more recent study by Sawamura and coworkers has revealed that [Et3Si (toluene)][B(C6F5)4] (Ic) has higher catalytic activity than (lb) [17]. With a loading of 1 mol% (Ic), the reaction of methyl acrylate with 1,3-cyclohexadiene at 0 °C is 

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