P-Toluenesulfinamides

In this connection, it is interesting to note that the extent of asymmetric induction in this reaction is strongly temperature dependent. Thus, the condensation carried out at 0°C yielded the mixture of diastereomeric sulfinamides 76 in a 3 1 ratio, whereas this ratio was 1 1 when the reaction was performed at -70°C. Diastereomeric A-a-methylbenzyl-p-toluenesulfinamides 77 were also prepared by Cram and Nudelman (116) in the reaction between sulfinyl chloride 61 and chiral (-)-a-methylbenzyl amine. 

Optically active iV-tosyl-N-methyl-p-toluenesulfinamide 80 was prepared (119) in low chemical yield by the reaction of optically active methyl p-tolyl sulfoximide 81 with 2 equiv of tosyl chloride in pyridine as solvent. The process of demethylation takes place with retention of configuration at sulfur. 

In this connection it is interesting that the steric course of the acid-catalyzed alcoholysis of the optically active (-)-( S)-A -diisopropyl-p-toluenesulfinamide 253 depends on the structure of the alcohol used. The results so far obtained are listed in Table 2 (246). 

Savile, C. K., Kazlauskas, R.J., The 3-(3-pyridine)propionyl anchor group for protease-catalyzed resolutions p-toluenesulfinamide and sterically hindered secondary alcohols. Adv. Synth. Catal, 2006, 348, 1183-1192. 

B. (S)-(+)-N-(Benzylidene)-p-toluenesulfmamide (3) 2 An oven-dried, 500-mL, one-necked, round-bottomed flask (Note 1), equipped with a magnetic stirring bar and rubber septum is charged with 10.35 g (66.8 mmol) of (S)-(-t-)-p-toluenesulfinamide (2). The reaction flask is placed under vacuum (1 mm) for 30 min to remove residual moisture. The vessel is then placed under an argon atmosphere and dichloromethane (135 mL) (Note 8) is added via cannula. The solution is stirred rapidly and 7.07 g... 

Chiral N-benzylidene-p-toluenesulfinamides p- and y-amino acids.1 Reaction of benzonitrile with CH3Li and then with (S)-l at 0° provides sulfinamide 2,... 

SULFINIMINES (THIOOXIMINE S-OXIDES) ASYMMETRIC SYNTHESIS OF METHYL (RM+)-p-PHENYLALANATE FROM (S)-(+)-N-(BENZYLIDENE)-p-TOLUENESULFINAMIDE. 

Bravo et al. treated (Ss)-(+)-p-toluenesulfinamide (63), prepared by hydrolysis of 44,23 with triphenylphosphine in the presence of DEAD to give the N-sulfinyl iminophosphorane 64 in 92% yield.45 The Staudinger, aza-Wittig reaction of 64 with methyl or ethyl trifluoropyruvate afforded the unstable sulfinimine 65. Attempts to purify the imino sulfinimines by flash chromatography resulted in hydrolysis. 

A particularly effective method for the asymmetric synthesis of both aldehyde-and ketone-derived sulfinimines recently introduced by Davis and co-workers is the condensation of (5)-(+)-p-toluenesulfinamide (63) with aldehydes and ketones using activated 4-A molecular sieves or titanium ethoxide [Ti(OEt)4].46 This procedure avoids the problem of removing the menthol by-product of the one-pot procedure (see Section II.D) which is sometimes problematic.23 Importantly, this methodology affords ketone derived sulfinimines 66 which are difficult to prepare by other means. 

Reduction of (R)-(-)-N-[ 1 -(triethoxymethyl)ethylidene]-p-toluenesulfinamide (115), prepared by addition of MeLi to triethoxyacetonitrile followed by the Andersen reagent 40, gave a 95% yield of 116 as a single diastereoisomer on... 

SCHEME 118. Reaction of (5)-(+)-iV-(benzylidene)-p-toluenesulfinamide with glycine enolates at... 

Chiral )V-benzylidene p-toluenesulfinamides were prepared by reaction of benzonitrile with an alkyllithium followed by addition of (—)-menthyl (S)-p-toluenesulfinate and converted into optically active amines and amino acids (eq 19). ... 

SULFINIMINES (THIOOXIMiNE S-OXIDES) ASYMMETRIC SYNTHESIS OF METHYL (R)-(+)-p-PHENYLALANATE FROM (S)-(+)-N-(BENZYLIDENE)-p-TOLUENESULFINAMIDE (Benzenepropanoic acid, p-amino-, (R)-, methyl ester from Benzenesulfinamide, 4-methyl-N-(phenylmethylene)- [S-(E)]-)... 

Sulfinimines (Thiooximine S-Oxides) Asymmetric Synthesis of (R)-(+)-(3-Phenylalanine from (S)-(+)-N-(Benzylidene)-p-Toluenesulfinamide. 

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