Alkyl p-toluenesulfinate

Chiral sulfinates are important intermediates that are widely applied in the synthesis of other classes of chiral organosulfur compounds and in their configurational correlations. Optically active sulfinates were first prepared in 1925 by Phillips (100) in two ways. The first consisted in the transesterification of racemic alkyl p-toluenesulfin-ates with chiral alcohols such as (-)-menthol and (-)-2-octanol yielding a mixture of two optically active sulfinates as shown in eq. [26]. The... 

Keywords p-toluenesullinic acid, alcohol, silica gel, microwave irradiation, alkyl p-toluenesulfinate... 

Synthesis of alkyl p-toluenesulfinates The reactions of aliphatic alcohols with p-toluenesulfinic acid are accelerated by microwave irradiation under solvent-free conditions in the presence of silica gel, affording a high-yielding synthesis of p-toluenesulfinate esters [121] (Eq. 37) ... 

An interesting method for the estimation of optical purity of sulfoxides, which consists of the combination of chemical methods with NMR spectroscopy, was elaborated by Mislow and Raban (241). The optical purity is usually determined by the conversion of a mixture of enantiomers into a mixture of diastereomers, the ratio of which may be easily determined by NMR spectroscopy. In contrast to this, Mislow and Raban used as starting material for the synthesis of enantiomeric sulfoxides a diastereomeric mixture of pinacolyl p-toluenesulfinates 210. The ratio of the starting sulfinates 210 was 60.5 39.5, as evidenced by the H NMR spectrum. Since the Grignard reaction occurs with full stereospecificity, the ratio of enantiomers of the sulfoxide formed is expected to be almost identical to that of 210. This corresponds to a calculated optical purity of the sulfoxide of 20%. In this way the specific rotations of other alkyl or aryl p-tolyl sulfoxides can conveniently be determined. 

Sodium toluene dispersion of, 55, 65 Sodium p-toluenesulfinate, 57, 103 Spiro[4 n] alkenones, 58, 62 Spiro[cyclopentane-l,l -indene] 55, 94 Squalene, 56, 116 Squalene, 2,3-epoxy, 56, 116 Stannic chloride, 56, 97 Steroids synthesis, 58, 85 E Stilbene, 55, 115,58, 73 z-Stilbene, 58, 133 Styrene, 56, 35,58, 43 Styrene glycol, 55, 116 Styrene glycol dimesylate, 55, 116 Succinic acid, 58, 85 Succinic anhydride, 58, 85 Sucunimide, 56, 50, 58, 126 Succimmide, Vbromo, 55, 28, 56, 49 SULFIDE CONTRACTION, 55, 127 Sulfide, dimethyl-, 56, 37 SULFIDE SYNTHESIS, 58, 143,58, 138 SULFIDE SYNTHESIS ALKYL ARYL SULFIDES, 58, 143 SULFIDE SYNTHFSIS DIALKYL SULFIDES, 58, 143 SULFIDE SYNTHESIS UNSYMMETRI-CAL DIALKYL DISULFIDES, 58, 147 SULFONYL CYANIDES, 57, 88 Sulfur tetrafluoride, 57, 51... 

O-and S-Akylation. This base facilitates esterification of carboxylic acids1 and S-alkylation of p-toluenesulfinic acids.2... 

Preparative Methods the synthesis of this compound was first reported by methylation of (R)-(+)-t-Butyl 2-(p-Tolylsulfinyl)acetate via enolate generation with lithium bases such as n-Butyllithium or t-Butyllithium at 0 °C and with only lodomethane as the alkylating agent (eq 1). The diastereomeric ratio was shown by H NMR to be 50 50 with BuLi and 42 58 with t-BuLi. The title compound was also prepared from (-)-(1R,2S,5R)-Menthyl (S)-p-Toluenesulfinate and the magnesium enolate of t-butyl propionate in 68% yield as a 1 1 ratio of the two possible diastereomers (eq 2). ... 

Alkyl Sulfoxides. Any Grignard reagent reacts with (-)-men-thyl (5)-p-toluenesulfinate and displaces the menthoxy group with complete inversion of configuration at sulfur (eq 2 R = Me, Et, n-CeHia ). 

Defunctionalization. removed. These include the ben the demethoxylation process in proceeds with good enantiosele propionanilides, which are alu by alkylation, are obtained fron LiCl. A p-toluenesulfinyl gnx reaction of a-(p-toluenesulfin serving its purpose. Dithioaor benzene. ... 

Oxoalkylbismuthonium salts react with a sodium salt of dibenzoylmethane to alkylate the active methylene carbon [304]. Treatment of a mixture of Ph3BiF2 and allyltrimethylsilane with lii, -O Hl, in the presence of excess electron-rich arenes yields allylated arenes via the Friedel-Crafts reaction (Scheme 14.149) [305]. The action of tBuOK on a mixture of alkenylbismuthonium salt and styrenes gives al-kylidenecyclopropanes in high yield (Scheme 14.150) [306]. Michael addition of sodium p-toluenesulfinate to a 1-hexynylbismuthonium salt results in the formation of 3-methyl-l-tosylcyclopentene [307]. 

Sulfone synthesis. The salt (1) reacts with alkyl halides in THF at 20-40° (2-4 hr.) to give alkyl 4-methylphenyl sulfones, usually in yields of 60-90%. The analogous reaction with sodium p-toluenesulfinate itself proceeds in much lower yields, mainly because 0-alkylation competes with S-alkylation. ... 

H-1,2-Diazepines. /3-Alkyl-a, 7,6-unsaturated ketones (1) react with tosylhydrazine to form 3,4-dihydro-2-tosyl-l,2-diazepines (2) rather than tosyl-hydrazones. The products eliminate p-toluenesulfinic acid when treated with base to form 3H-l,2-diazepines (3). Formation of (2) has been observed only... 

P-Alkylation. The Michael-Arbuzov reaction of chloromethyl p-tolyl sulfide with trimethyl Phosphite or triethyl phosphite yields dimethyl- or diethylphosphonylmethyl p-tolyl sulfides, which are important intermediates for the synthesis of vinyl sulfides and sulfoxides, as well as for optically active derivatives of dimethylphosphonylmethyl p-tolyl sulfoxide (eq 7). This method of preparation of the chiral p-tolylthio monosulfoxide is complementary to the reaction using dimethylphosphonyl-methyllithium and (—)-(5)-menthyl p-toluenesulfinate in which the (+)-(7 isomer is obtained in high 3ueld and high optical purity (eq 8). The lithio dimethylphosphonylmethyl p-tolyl sulfoxide reacts with aldehydes and ketones to give the corresponding vinyl sulfoxides, which can be converted into optically active allylic alcohols (eq 9). ... 

Alkylation of arenesulfinate salts is a very general reaction for the preparation of alkyl sulfones. Reaction conditions utilizing alcoholic or dipolar aprotic solvents are t) ical, but phase-transfer conditions have been described. Reaction with reactive halides is generally facile (eq 1) triflates have likewise been displaced with ease by p-toluenesulfinate. ... 

Sulfonyl and Sulfinyl Chlorides from Sulfonic and Sulfinic Acids. Alkyl or arylsulfonyl chlorides are prepared by heating the acid with thionyl chloride DMF catalyzes this reaction. (+)-Camphorsulfonyl chloride is produced in 99% yield without a catalyst. Use of the salts of sulfinic acids minimizes their oxidation p-toluenesulfinyl chloride is produced in about 70% yield from sodium p-toluenesulfinate dihydrate with excess thionyl chloride. Phosphorus(V) Chloride is more commonly used for this transformation. 

---