Unsaturated ketones reactions

Dihydroazines based on a,p-unsaturated ketones reactions 06COC297. 

Ammonia and amines add readily to the double bond in a, -unsaturated ketones (reaction 77) and nitro compoimds (reaction 78) catalysis being usually unnecessary even for aromatic amines. 

Similarly Michael additions of thiols and nitroalkanes to a,3— unsaturated ketones [reactions 2 and 3] catalysed by anhydrous potassium fluoride in the presence of the above ammonium salts produces optical yields of up to 35%. Another unambiguous 

These include the cycloaddition between a ketene and a Schiff base (reaction 1), two addition reactions to a,3 unsaturated ketones (reactions 2 and 3), and the condensation of two molecules of aldehyde to yield an oxirane derivative (reaction 4), see Scheme 2. 

Figure 49.2. Catalytic oxidation of the allylic alcohols 11, 16 and 17 with FePcCli -S to the corresponding a, 5-unsaturated ketones. Reaction conditions 0.125 M allylic alcohol in acetone, 0.5 % mol FePcClis-S, 1.3 mmol of dry TBHP, 40T, 3 h.

The aldol reactions of titanium enolates generated in situ were reported by Harrison [27] to give excellent yield and selectivity for syn aldol products, as shown in Table 2.10. However, methyl ketones tended to eliminate under the reaction conditions and provided a,/i-unsaturated ketones. Reactions with propiophenone and benzaldehyde provided excellent yields of aldolates, with syn aldols being the major product (95 5 ratio). The stereochemical outcome was rationalized by Zimmerman-Traxler transition state model 67. 

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