Organocatalytic transformations and asymmetric α-halogenation have become an important and dynamic research topic in organic chemistry in recent years. Despite the growing research in asymmetric halogenation of carbonyl compounds, such as aldehydes and ketones, there are no current examples in the ...
Dehydrohalogenation of α-haloketones by heating with 2,4-dinitrophenylhydrazine(1 → 2)or with LiCl in DMF (3 → 4). Sign in to download full-size image Cortisone acetate (4).A solution of 4-bromo-3-keto steroid3(9.5 g, 2 mmol) and lithium chloride (0.255 g, 6 mmol) in DMF (...
Equilibrium Amounts • For aldehydes and ketones, the keto form is greatly favored at equilibrium. • An enantiomer with an enolizable hydrogen can form a racemic mixture. Acidity of αHydrogens • pK a for αH of aldehyde or ketone ~20. • Much more acidic than alkane or ...
1,1-Disubstituted and trisubstituted alkenes were converted into the corresponding beta,gamma-unsaturated amines 4 via three steps: the initial formation of alpha,beta-unsaturated diphenylsulfonium triflates 2 from alkenes and diphenyl(trifluoromethanesulfonyloxy)sulfonium trifluoromethanesulfonate (1), foll...
For example, the substituents of a substituted alkyl may include substituted and unsubstituted forms of amino, imino, amido, sulfonyl (including sulfonate and sulfonamide), as well as ether, alkylthio, carbonyl (including ketones, aldehydes, carboxylates, and esters), fluoroalkyls such as —CF3...
Organocatalytic transformations and asymmetric alpha-halogenation have become an important and dynamic research topic in organic chemistry in recent years. Despite the growing research in asymmetric halogenation of carbonyl compounds, such as aldehydes and ketones, there are no current examples in the ...
halogenationA series ofgem-difluorocyclopropyl acetals and ketals are easily obtained in moderate yields from the 12 cycloaddition of difluorocarbene to 1,3-dioxolanes of α,β-unsaturated aromatic aldehydes and ketones. Hydrolysis of these fluorinated compounds under acidic conditions either gives the...
Electrospray ionization mass spectrometric study on the direct organocatalytic α-halogenation of aldehydes . Angew Chem Int Ed ( 2007 ) 46 6915 .Marquez, A.; Fabbretti, F.; Metzger, J. O. Electrospray Ionization Mass Spectrometric Study on the Direct Organocatalytic a-Halogenation of Aldehydes. ...
halogenationorganoboronoxidationtrifluoromethylationThe synthesis of halogenated and trifluoromethylated alpha-boryl ketones via a one-pot oxidative difunctionalization of alkenyl MIDA boronates is reported. These novel densely functionalized organoborons bearing synthetically and functionally valuable carbonyl, halogen...