958. Nucleophilic displacements in organic sulphites. Part I. The positions of bond fission in the hydrolyses of some 1 : 2- and 1 : 3-cyclic sulphites

Abstract

The positions of bond-fission in the hydrolyses of ethylene sulphite, propylene sulphite, meso-2 : 3-butylene sulphite, tetramethylethylene sulphite, trimethylene sulphite, and 1 : 3-butylene sulphite have been determined isotopically under acidic and alkaline conditions. Sulphur-oxygen bond-fission occurs in all the examples studied. It has been shown, for ethylene and for trimethylene sulphite, that the organic sulphite, originally isotopically normal, is still normal when recovered after partial hydrolysis in isotopically enriched water under either acidic or alkaline conditions.GARNER and LUCAS showed that the formation, followed by the acid-or alkali-catalysed hydrolysis, of 2 : 3-butylene sulphite proceeded without change in the optical activity of the butane-2 : 3-diol used as starting material. They concluded that these hydrolyses proceed with sulphur-oxygen bond-fission. Foster, Hancock, and Overend have studied the hydrolyses of the cyclic sulphites of the cyclohexane-1 : 2-diols. The transisomer gave the trans-diol; the cis-isomer gave the cis-diol in acidic solution, and mainly the trans-with some cis-diol, in alkaline solution. From this they concluded that some Garner and Lucas,

Synthesis and Evaluation of Cyclic Sulfite Diesters as Sulfur Dioxide (SO2) Donors

“…In the cases of 12-15,t he closely similar pK a values for the alcohols imply that any difference in SO 2 yields must be due to increased steric hindrance at the carbon atoms bearing the sulfite ester.T he diesters 12, 14,a nd 15 gave SO 2 yields > 20 % after 30 min, whereas pinacold erivative 13 gave only a2 % yield of SO 2 .T hese results suggest that when the leaving groups were similar the important determinant of observed reaction rates was steric factors, supporting the proposed mechanism (Scheme 2). These resultsa re also consistent with previous reports [20] of 1,2-cyclic sulfite diesters undergoing nucleophilic substitution with various nucleophiles such as chloride, azide, and (CH 3 OOC) 2 HC À at one of the activated carbon atoms (Scheme 2). [20][21] The hydrolysis of cyclic sulfite esters of normal or cis or trans diols under acidic (cat.…”

“…These resultsa re also consistent with previous reports [20] of 1,2-cyclic sulfite diesters undergoing nucleophilic substitution with various nucleophiles such as chloride, azide, and (CH 3 OOC) 2 HC À at one of the activated carbon atoms (Scheme 2). [20][21] The hydrolysis of cyclic sulfite esters of normal or cis or trans diols under acidic (cat. H 2 SO 4 /HClO 4 )o rb asic (2 equiv NaOH) reflux conditions resultsi ns ulfur-oxygen bond fission to give the corresponding diols without any change in stereoconfiguration.…”

“…H 2 SO 4 /HClO 4 )o rb asic (2 equiv NaOH) reflux conditions resultsi ns ulfur-oxygen bond fission to give the corresponding diols without any change in stereoconfiguration. [20,22] In order to study electronic effects on decomposition, diesters 16 and 17 were incubated in pH 7.4 buffer.S O 2 yields of 93 and 98 %, respectively,w ere recorded (Table2,e ntries 5a nd 6). These compounds contain an electron-withdrawing substituent, relative to ethylene glycol diester 12.T he electronwithdrawing nature of the ester enhances the electrophilicity of the closer carbon atom bearing the sulfite functionalg roup, thus contributing to an increased rate of displacement.…”

Synthesis of Cyclic Sulfite Diesters and their Evaluation as Sulfur Dioxide (SO2) Donors

“…These results suggest that when the leaving groups were similar the important determinant of observed reaction rates was steric factors, supporting the proposed mechanism (Scheme ). These results are also consistent with previous reports of 1,2‐cyclic sulfite diesters undergoing nucleophilic substitution with various nucleophiles such as chloride, azide, and (CH 3 OOC) 2 HC − at one of the activated carbon atoms (Scheme ) . The hydrolysis of cyclic sulfite esters of normal or cis or trans diols under acidic (cat.…”

“…The hydrolysis of cyclic sulfite esters of normal or cis or trans diols under acidic (cat. H 2 SO 4 /HClO 4 ) or basic (2 equiv NaOH) reflux conditions results in sulfur‐oxygen bond fission to give the corresponding diols without any change in stereoconfiguration …”