Sulphonylhydrazones reactions

An alternative milder procedure is the reduction of the corresponding toluene-p-sulphonylhydrazones with catecholborane, followed by decomposition of the intermediate with sodium acetate in the presence of dimethyl sulphoxide, or with tetrabutylammonium acetate.1 These methods, which do not have the disadvantages of the Clemmensen reduction, are illustrated by the preparation of ethylbenzene from acetophenone (Expt 6.4, Methods A and B). Outline mechanisms for these reactions are given below. 

Method B. The toluene-p-sulphonylhydrazone of acetophenone (0.721 g, 2.5 mmol) (1), m.p. 140—141.5 °C, is placed in a flame-dried, nitrogen-filled flask containing 5 ml of chloroform. Catecholborane (0.52 ml, 5.0 mmol) (Section 4.2.7, p. 420) is added and the reduction allowed to proceed for 2 hours at room temperature (2). Methanol (1 ml) is added to destroy the excess of hydride followed by the addition of tetrabutylammonium acetate (0.7 g, 2.5 mmol). The reaction mixture is stirred for 4 hours when g.l.c. analysis indicates a 94 per cent yield of ethylbenzene. The product is isolated by distillation, yield 0.21 g (79%), b.p. 132-136 °C. 

Azine formation, shown in reaction (3), took place at 175-250° in the heated inlet system of a mass spectrometer but was not observed with a direct inlet system (Blythin and Waight, 1967 Nakata and Tatematsu, 1967). However, earlier it had been observed that similar azine formation occurred in sulphonylhydrazones (4) even with a direct inlet system... 

The C-nor-D-homo rearrangement has been effected by methods other than i2j sulphonate solvolysis, including the deamination of a i2jS-amine (7) [iii] and the decomposition of i2-toluene- sulphonylhydrazones (8) under basic conditions [io8,iog,ii2]. It is both convenient and instructive to consider these reactions together, especially since the com-... 

Conversion of the readily available thujone (211) to 3-thujene (212) has been effected in two laboratories. Thermolysis of the sodium salt of thujone p-toluene-sulphonylhydrazone leads to a 1 1 mixture of the more accessible 2-thujene (210) and 3-thujene (212)/ ° Baldwin and Krauss have raised the yield by treating the same p-toluenesulphonylhydrazone with sodium in acetamide solution. In this reaction 97% of hydrocarbons was obtained, 80% of which was 3-thujene and 20% was y-terpinene (213). The latter method has the advantage of not producing 2-thujene, which is extremely difficult to separate from 3-thujene. 

The optical purities obtained were generally low (<40%). The acid-catalysed reaction of 6-deoxy-l,2-0-isopropylidene-3-0-methyl-a-D-xy/o-hexofuranos-5-ulose 5-(toluene-p-sulphonylhydrazone) (433) with methyl phenylphosphonite has been used in a novel method for the synthesis D-gluco- and L-ido-pyranose derivatives containing a phosphorus atmn in the hemiacetal ring (Scheme 78). ... 

An analogous sequence of reactions with methyl 2,3-dideoxy-(lS)-pentopyranosid-4-ulose 4-(toluene-p-sulphonylhydrazone) (434) afforded l,5-di-0-acetyl-2,3,4-trideoxy-4-C-(phenylphosphinyl)-DL-gfiycero-pentofuranose (435). The Abramov reaction of 2,3 5,6-di-O-isopropylidene-a-D-mannofuranose with dimethyl phosphite yielded the oxaphosphorinane (436) by intramolecular transesterification. ° ... 

Synthetic Aspects.— The extraction of reaction mixtures with aqueous sodium hydrogen sulphite has been advocated as a mild procedure for the efficient removal of norbornenone and norbornenol impurities.Deuteriated olefins can be efficiently synthesized from the corresponding arenesulphonylhydrazones. The reaction of R R CHC(R ) NNHS02Ar with an alkyl-lithium in tetramethylethylenediamine produces R R C (CR which, upon quenching with water (or D 2 O), is converted into olefin R R C=CHR (or R R C=CDR ). Treatment of the sulphonylhydrazone derived from camphor by this method gave (442) in quantitative yield with a 95 % [ H2] analysis. ... 

The generation of carbenes by reaction of metastable singlet carbon atoms with aldehydes and ketones has been described in detail the distribution of intramolecular rearrangement products is identical with that observed from toluene-p-sulphonylhydrazone-derived carbenes. Suitably substituted carbenes generated in this manner, e.g. that prepared from (4), can be trapped by olefins, when the cyclopropane (5) produced retains the original olefin geometry, indicative of a singlet species. 

Methyl vinyl ketone, when converted into the sulphonylhydrazone (189), undergoes the Shapiro reaction to generate 2-lithiobuta-l,3-diene (190), which then reacts with aldehydes to give 2-substituted dienes (191) in moderate yield. ... 

The first representative of a new type of helical structure (419), having features of both helicenes and cyclophanes, has been formed by pyrolysis of a sulphone made from the bis(bromomethyl)-quaterphenyl (420a) and the corresponding dithiol (420b). An intramolecular carbene-insertion reaction involving the helicene skeleton has been reported in which l-formyl-[6]helicene toluene-p-sulphonylhydrazone (421) is converted into (422), the structure of which has been determined unambiguously by H and n.m.r. spectroscopy. 

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