To unsaturated ketone

A number of alternative multi-step procedures for the synthesis of a-tert-alkyl ketones are known, none of which possess wide generality. A previous synthesis of 2-tert-penty1cyclopentanone involved reaction of N-1-cyclopentenylpyrrol 1 dine with 3-chloro-3-methy1-l-butyne and reduction of the resulting acetylene (overall yield 46 ). However, all other enamines tested afford much lower yields. Cuprate addition to unsaturated ketones may be useful in certain cases. Other indirect methods have been briefly reviewed. ... 

Addition of silyl enol ethers or silyl ketene acetals to unsaturated ketones or esters... 

CO 1 0 c 1 X r Nucleophilic substitution and conjugate addition to unsaturated ketones ketones from acyl chlorides b,c... 

Pudovik, A.N. and Arbuzov, B.A., Addition of dialkyl phosphites to unsaturated ketones, nitriles, and esters, Dold. Akad. Nauk S.S.S.R., 73, 327, 1950. 

Finally, Holm and 0gaard Madsen (1992) determined the secondary /3-deuterium KIEs for the addition of /3-deuterated Grignard reagents to unsaturated ketones. Hie authors attributed the small, <5%, KIEs they found in these radical reactions to opposing steric and hyperconjugative effects. 

In basic aqueous solutions with a [Rh(COD)2]BF4 catalyst, phenyltin trichloride was found to react with aromatic aldehydes or unsaturated ketones. In the presence of a strong aqueous alkali (KOH) PhSnCU is readily hydrolysed and the products of this reaction, such as e.g. PhSn(OH)3 add to the carbonyl function of aldehydes or undergo conjugate addition to unsaturated ketones (Scheme 6.35). In the absence of KOH no reaction takes place at all. Yields are generally high [73]. 

Michael-like nucleophilic attack of enamine on to unsaturated ketone note ketone is more electrophilic than ester Me... 

Various mechanisms have been proposed for these reactions, but little can be deduced yet from such a scanty supply of examples the light-induced addition of water to unsaturated ketones seems to represent a relatively unattended area of photochemistry. 

Addition of organometallic compounds to unsaturated esters 5-20 Addition of tin and mercury hydrides to unsaturated ketones 5-22 Free-radical addition of carboxylic esters to olefins... 

Addition of organometallic compounds to unsaturated ketones 5-19 Addition of boranes to unsaturated... 

The carbonyl group in condensed 4f/-pyran 263b was reduced by condensation with tosylhydrazine followed by borohydride.290 The aldehyde group in 607b was aldolized with acetophenone to unsaturated ketone 607c or oxidized to carboxylic acid 607d with molecular oxygen.86... 

Michael addition of stabilized carbanions to unsaturated ketones or esters is a useful C—C bond forming reaction. As shown in Scheme 103, 5 mol % potassium ferf-butoxide complexed with a chiral crown... 

Organomagnesium and organolithium compounds can add both 1,2 and 1,4 to alkenones, and the relative importance of each mode of addition depends on the structure of the reactants. This sort of dual behavior can be a nuisance in synthetic work because it leads to separation problems and low yields. Organocopper compounds are a great help in this situation because they show a very high selectivity for 1,4 addition and add to unsaturated ketones in excellent yield ... 

Unsaturated alcohols can be oxidized to unsaturated ketones by chromic acid, because chromic acid usually attacks double bonds relatively slowly ... 

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