Cyclohexanones Michael-type addition

In a Michael-type addition 192 is converted by treatment with mesityl oxide (207) or methyl acrylate (209) under equal conditions (TiCl4) to 1 -phenyl-3,3-di-methyl-l,5-hexanedione (208) and methyl 7-benzoyl-butyrate (210)14i respectively. 193 reacts with meta-chloroperbenzoic acid (87) to yield 2-trimethylsiloxy-cyclohexanone (2ii)142 ... 

Ruder, S.M., and Kulkarni, V.R., Michael-type additions of 2-(diethoxyphosphinyl) cyclohexanone to activated alkenes and alkynes, J. Chem. Soc.. Chem. Commun., 2119, 1994. 

The Michael-type addition of cyclohexanone imines (210 = H, Me), reacting as... 

Intermediate enolates derived from Michael-type processes can be isolated. For example, enantiomerically pure enolate (5 )-131 can be isolated, as is the case of the almost enantiomerically pure enolate (5 )-131, prepared by 1,4-addition of the phenyl-substituted borane 130 to enone 129, in the presence of a substoichiometric amount of the chiral rhodium mediator [Rh(OMe)(COD)]2-(5 )-BINAP (COD = 1,5-cyclooctadiene, equation 33). Protonation of (5 )-131 with methanol leads to cyclohexanone (5 )-132 in good yield with no loss of enantiomeric purity (equation 34). The protonation is presumably diastereoselective, taking place on the less hindered face of (5)-131, away from the neighbouring phenyl group, as can be inferred from the stereochemical outcome (133)... 

The substitution of an acetic ester residue on the /3 carbon of cyclohexanone III points to a Michael-type 1,4 addition of the anion derived from II and base. This logical first step allows us to reformulate the problem in terms of a nitrile jump to the a carbon of IV in what is in essence a 1,3-nitrile shift. There are at least two ways to do this. 

The net effect of the Stork enamine sequence is the Michael addition of a ketone to an a, -unsaturated carbonyl compound. For example, cyclohexanone reacts with the cyclic amine pyrrolidine to yield an enamine further reaction with an enone such as 3-buten-2-one yields a Michael-type adduct and aqueous hydrolysis completes the sequence to provide a 1,5-diketone product (Figure 23.8). 

Two new types of optically active 1,3-oxazines (41) were synthesized by Rassat and Rey (74T265, 74T3315). The epimeric 1,3-amino alcohols 40, prepared from (-l-)-pulegone 39 by Michael addition of ammonia and subsequent reduction, were cyclized with acetone, cyclohexanone, and 4-tert-... 

Chen and coworkers have reported a new domino Michael-Michael addition reaction between a,a-dicyanoalkene [26] derived from cyclohexanone and benzyli-deneacetone, resulting in a stepwise [4 + 2]-type cycloaddition to afford almost enantiopure bicyclic adduct 15. In contrast to the completely inert function of secondary ammonium salt, a primary amine, 9-amino-9-deoxyepiquinine lo [27], in combination with trifluoroacetic acid, was found to be highly efficient in the activation of the a, 3-unsaturated ketone by tandem iminium-enamine catalysis (Scheme 10.21) [28],... 

The asymmetric Michael addition of secondary enamines has been reviewed by d Angelo [179]. Some of the more selective examples of this type of reaction are listed in Table 5.8. It is significant that these Michael additions are highly regio-selective, reacting virtually exclusively at the more highly substituted carbon, which affords a,a-disubstituted (quaternary) cyclopentanones, cyclohexanones, furans,... 

As a novel type of proline-based secondary amine, Du devised the chiral binaphthyl bis-sulfonamide 19 and demonstrated that it could act as an efficient catalyst for the asymmetric Michael addition of cyclohexanone to nitrostyrene, giving rise to the corresponding y-nitroketone derivative with high levels of diastereo- and enantioselectivity (Scheme 7.32) [56]. 

Asymmetric Michael addition reaction represents one of the most extensively explored organoctalytic transformations. Chiral secondary amines such as pyrrolidines have been proved to very effective catalysts for the reactions of Michael donors such as cyclohexanone and aldehydes [31]. Ala-Ala dipeptide 57 [32] was firstly found to be viable catalyst for the reaction of cyclohexanone and nitrosty-rene. Later, some primary amine-amide type catalysts such as 55 [33a], 56 [33b-c] and 58 [33d] have also been indentilied for the same reactions (Scheme 5.16) with slightly lower activity compared with typical chiral pyrrolidine catalysis. 

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