Conjugated carbonyls, and

A logical extension of the Abramov- and Pudovik-type reactions at carbonyl carbon is the conjugate addition of the phosphorus reagents at distant sites of conjugated carbonyl and related systems. A wide range of such Michael addition reactions, many of significant practical... 

Gycloisomerization of a disubstituted alkyne sometimes required activation of the alkyne by the addition of a conjugated carbonyl and performing the reaction at a higher temperature as in Equation (38). The geometry of the alkene determines the regioselectivity of the /3-hydride elimination, as ( )-60 gave predominantly 61 (Equation (38)), while 62 was the major product of the cycloisomerization of (Z)-60 (Equation (39)). 

FO analysis allows us to go a little deeper into these reactions. According to STO-3G calculations, the largest LUMO coefficient is at C4 in the free (i.e. noncoordinated) conjugated carbonyl and at C2 in the corresponding ate complex. Therefore, Loupy and Seyden predicted that even a hard reagent such as LiAlH4 should be able to give... 

Infrared spectrum The two most significant peaks are at 1680 cm (conjugated carbonyl) and 1600 cm (aromatic C=C). 

This chapter begins with a detailed examination of the evolution of the theory of nucleophilic attack on a chiral aldehyde or ketone, from Cram s original rule of steric control of asymmetric induction to the Felkin-Anh-Heathcock formulation. Then follows a discussion of Cram s simpler rigid model (chelate rule), then carbonyl additions using chiral catalysts and chiral (nonenolate) nucleophiles. The chapter concludes with asymmetric 1,4-additions to conjugated carbonyls and azomethines. 

The most vital and crucial aspect of construction reactions are essentially comprise of such reactions which help in developing the basic carbon-carbon single bonds (perhaps on which the rest of the pyramid is made subsequently). Therefore, such reactions primarily need a carbon nucleophile in order to make available the electrons for the bond formation besides, a carbon electrophile to accept them appropriately. In usual practice, the nucleophiles are typified by carbanions or their equivalent substitutes and also the jr-bonds of benzene rings (aromatic) or alkenes (aliphatic). Likewise, the electrophiles are examplified by electron-deficient carbon-atoms commonly attributed by three t3rpes of entities, such as carbonyls conjugated carbonyls and C-atoms that rapidly become electron-deficient on being deprived of an attached functional group. 

Shortly after Sadighi and Buchwald s 2003 report, Nolan reported that [(IPr)CuCl] could be used in the hydrosilylation of simple ketones, leading to the silylated alcohols in high yields. Subsequent work permitted the development of fine-tuned catalytic systems for different classes of carbonyl compounds. Hence, while [(IPr)CuCl] was found optimal for the 1,4-reduction of conjugated carbonyls and 1,2-reduction of simple ketones, [(ICy)CuCl] proved more efficient for hindered carbonyl substrates and [(SIMes)CuCl] turned out to be the best choice for heteroaromatic ketones (Scheme 11.1). Other NHC architectures e.g. six-membered diamino carbenes) and alternative... 

Polar groups, eg, carbonyl and sulfonyl, that are capable of conjugation with the aromatic ring increase the glass-transition temperature, eg, to 245°C for the sulfonyl group, as in (5). 

Coniine, molecular model of. 28 structure of, 294 Conjugate acid, 49 Conjugate base, 49 Conjugate carbonyl addition reaction, 725-729 amines and, 727 enamines and, 897-898 Gilman reagents and, 728-729 mechanism of, 725-726 Michael reactions and, 894-895 water and. 727 Conjugated diene, 482... 

When both the carbonyl group and the sulfinyl group of a /J-ketosulfoxide are attached to the same carbon atom of a carbon-carbon double bond, then addition of nucleophiles can occur at the electrophilic -carbon atom (i.e., 1,4-addition, conjugate addition) and/or... 

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