Sulfonyl ketones

Arylsulfonyl chlorides and enamines reacted to give sulfonated enamines (452,453,474). The latter could be hydrolyzed to the corresponding sulfonyl ketones. 

Intramolecular carbene insertion (e.g. 1 —> 3) has long been a useful method for ring construction. Masahisa Nakada of Waseda University in Tokyo now reports (J. Am. Chem. Soc. 125 2860, 2003) that with the addition of the ligand 2 this process can be made highly enantioselective. As the starting diazo ketone 1 is easily prepared by diazo transfer to the sulfonyl ketone, this should allow facile entry to enantioenriched cyclopentanones and cyclohexanones. 

The catalyzed reduction has a wide scope for various ketones with excellent enantioselectivity (Table 6). The protocol was successfully applied to the reduction of a-siloxy and tetahydropyranyloxy ketones (entry l),1074 cr-bromo and cr-chloroacetophenne (entry 2),1091-1094 trihalomethyl ketones (entry 3),1095-1099 a-sulfonyl ketones (entry 4),1100... 

Trost and coworkers [116] found that palladium-catalyzed intramolecular allylic alkylation to a-sulfonyl ketones is a good means of performing macrocyclization. This reaction involves the intermediacy of a tt-allylpalladium complex as an enolonium equivalent to initiate cyclization. For instance, this method was used in the synthesis of the cytochalasin ( — )-aspochalasin B (201) [117]. As shown in Scheme 66, cyclization of the linear precursor 199 using 10 mol% (Ph3P)4Pd in the presence of 10 mol% DPPP in THF created the 11-membered carbocycle 200 as a single diastereoisomer in 49% yield. 

Messinger. P. and Gompertz, J., Darstellung von Sulfonyl-keton-Mannich-bascn, Arch. Pharm.. 308, 7.27. 1975. 

All the members of this class of compounds contain an aromatic ketone group, the most representative systems being benzoin [71], benzoin ethers [72], dialkoxy-acetophenones [73], hydroxyalkylphenones [74], benzoyloxime esters [75] and, more recently, benzoylphosphine oxides [76], a-hydroxymethylbenzoin sulfonic esters [77], sulfonyl ketones [78] and morpholino ketones [70],... 

Further examples are the ready reductive desulfurizations of a-keto sulfones by Li in liquid NHy-THF, 2 of hydroxy a-keto sulfones by Li-EDA-THF, of a,(3-unsaturated-"y-sulfonyl ketones by Li in liquid NH3, and of chiral hydroxy sulfones by Li-EDA. ... 

The potent reductant Smh readily reduces a-alkylthio, a-sulfinyl and a-sulfonyl ketones at -78 °C A mixture of iron(II) polyphthalocyanine and thiophenol has been used to reduce a-halo, a-alkylthio, and a,a-bis(alkylthio) ketones. The iron compound apparently reacts as an electron transfer mediator the actual source of electrons is the thiophenol, which is converted to diphenyl disulfide in the course of the reaction. 

In contrast to the ready reductive cleavage of a-sulfonyl ketones, reductive dephosphonylation of P-ketophosphonates is surprisingly difficult. All attempts to produce methyl cyclohexyl ketone from di-Zez7-butyl 2-cyclohexyl-2-oxoethylphosphonate by various reducing agents failed... 

This approach was also used for phosphine oxides [256] and has been already extended, in the last few years, to other structures such as other hydroxyalkyl ketones [257], [4-(methylthio) phenyl]-2-morpholinopropanone [258], Barton s esters [66], sulfonyl ketones [250], and so on. 

Sulfonic (-SO3H) and Sulfinic (-SO2H) Acid-Based Nonsalt Photoinitiators Photosensitive tosylate esters of nitrobenzyl [65] and benzoin [73], sulfonyl ketones [67,68], and diphenyl disulfones [68] can be employed in cationic photopolymerization, especially in photolithography and chemical amplification processes. The advantages of these photoinitiators are the ease of synthesis, the absorption wavelengths suitable for deep-UV curing and the high yield of acid formation [65]. 

D. Ruhlmann and J.P. Fouassier, Structure-property relationships in photoinitiators of polymerization. 8. Sulfonyl ketone derivatives. Eur. Polym. J. 1993, 29(8), 1079-1088. 

Oxidative desulfonylotion a-diketones.1 The potassium enolatc of an a-sulfonyl ketone on oxidation with a typical oxaziridine of this type, 2-[(/>-chlorophenyl)sulfonyl]-... 

Knoevenagel reaction. As surrogate for benzaldehyde in the condensation with active methylene compounds, the benzenesulfonimine is superior. In the presence of EtjN in chloroform the reaction with, inter alia, /8-diketones, )3-keto esters, a-sulfonyl ketones, a-nitro esters, and malononitrile proceeds at room temperature. 

Cleavage of cyclic a-chloro-a-sulfonyl ketones. The base causes ring open-ng to give methyl w-chloro-w-sulfonylalkanoates. On the other hand, Favorskii -earrangement is the favored pathway when piperidine is used instead of NaOMe. 

The anions of malonate esters, cyclopentadiene, p-keto esters, ketones, aldehydes, a-nitroacetate esters, Meldrum s acid, diethylaminophosphonate Schiff bases, p-diketones, /3-sulfonyl ketones and esters, andpolyketides represent the wide variety of carbon nucleophiles effective in this reaction. Generation of the stabilized anions normally is... 

Keywords a,p-Unsaturated ketones, sodiump-toluenesulfinate, iron(III) chloride, trimethysi-lyl chloride, dichloromethane, room temperature, conjugate addition, p-sulfonyl ketones... 

To a stirred solution of a,p-enone (1 1 mmol), TMSCl (1.2 mmol), and sodium sulfinate (2 1.5 mmol) in dichloromethane (3 mL), FeCls (20 mol%) was added, and stirring was continued at room temperature for 16 h to complete the reaction (monitored by TLC). After completirai of the reaction, the reaction mixture was quenched with saturated solution of sodium bicarbonate. The aqueous layer was extracted with EtOAc (3 x 20 mL), and the combined organics were dried over anhydrous Na2S04, concentrated in vacuo, and purified by column chromatography on Si02 to furnish the pure product of p-sulfonyl ketone 3. AU products were characterized by IR, NMR, NMR, and MS spectral analyses. 

The same tandem procedure can be carried out using vinyl disulfones as electrophiles to provide the corresponding y-sulfonylated ketones 23 in high yields and diastereo- and enantioselectivities (Scheme 45) [76]. Sulfone derivatives are tunable synthetic entities [78]. For example, the homolytic cleavage of disulfones... 

A few benzoin derivatives decompose by photofragmentation mechanisms other than Norrish Type I. For example, a-halogen acetophenones [28], oxysulfonyl ketones [29], and sulfonyl ketones [30] sufficiently undergo p-cleavage upon UV irradiation and may be used for initiation, a-Dimethylamino-substituted benzoin undergoes both a-cleavage and P-pho-... 

Selective migrations on addition of a base have also been achieved starting from a-chloro-a-sulfoxidyl ketones [424] or a-chloro-a-sulfonyl ketones [425]. In the latter case, enantiopure substrates lead to the formation of fi-sulfonyl carboxyhc adds with excellent enantiocontrol. a-Selenium derivatives are oxidized to a-arylalkanoic derivatives by peradds [426]. 

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