Sulphenyl Chlorides Research Articles

Selective functionalisation of 1,3-dienes via organosulphur intermediates

The 1,2-adducts from 1,3-dienes and sulphenyl chlorides are shown to be useful intermediates by their conversion into a variety of functionalised alkenes.

1,3,5,2,4-Trithiadiazepine

1,3λ4δ2,5,2,4-Trithiadiazepine (6) and its benzo derivative (4) are stable crystalline compounds which are synthesised from bis(sulphenyl chlorides) and bis(trimethylsilyl)sulphurdiimide; spectroscopic and chemical properties show the heterocyclic ring to be a 10π aromatic system.

Ethyl and methyl thioxoacetates, dienophilic thioaldehydes formed from sulphenyl chlorides by 1,2-elimination

Ethoxycarbonyl- and methoxycarbonyl-methanesulphenyl chlorides react at room temperature with triethylamine to form ethyl and methyl thioxoacetates, respectively. Generation of the transient thioladehyde, ethyl thioxoacetate (2a), in the presence of the conjugated dienes 2,3-dimethylbuta-1,3-diene, thebaine (7), cyclohexa-1,3-diene, anthracene, and 9,10-dimethylanthracene gave adducts formed by cycloaddition of the thial group to the diene systems. The cycloadduct (8), derived from thebaine (7) at room temperature, isomerised at 111 °C to give the thermodynamically more stable adduct (9) by dissociation and recombination. The cycloadducts of anthracene and 9,10-dimethyl-anthracene likewise dissociated at 111 °C thereby providing a convenient, ‘clean’ source of ethyl thioxoacetate. When the anthracene adduct was heated with (–)-β-pinene, two ‘ene’ products were obtained, the major product (17; R = CO2Et) arising by C–S and the minor product (18; R = CO2Et) by C–C bond formation.

Semisyntoesis i - cleavage op methionyl peptide bonds by sulphenyl chlorides.

Methoxycarbonyl sulphenyl chloride (Scm.Cl) and o -nitrophenyl-sulphenyl chloride (Nps.Cl) have been shown to cleave methionyl peptide bonds in a manner similar to that found with cyanogen bromide. These new methods of cleavage of methionyl peptide bonds were illustrated by digestion of H.Gly.Het.Ala.OH trifluoroacetate, the (1–32) fragment of adrenocorticotropic hormone {(1–32) ACTH} and Hen Egg-White Lysozyme.

Stereospecific conversion of cyclic phosphorothioates into chlorophosphates

The reaction of the individual diastereoisomeric cyclic phosphorothioates 2a, 2b in the trans-2,4,7-trioxa-3-phosphabicyclo (4.4.0) decane and 4a, 4b in the trans-2,4,7-trioxa-3-phosphabicyclo (4.3.0) nonane series with sulphuryl chloride affords the corresponding sulphenyl chlorides 5a, 5b, 6a, 6b with retention of the configuration of the phosphorus atom. The reaction of the latter with phosphorus trichloride leads stereospecifically to the chlorophosphates 7a, 7b, 8a and 8b with full retention of configuration at phosphorus.

Ring expansion reactions of 1,3-dithiolans and 1,3-dithians. A new synthesis of dihydro-1,4-dithiins and dihydro-1,4-dithiepins

A mild and convenient method for ring expansion of 1,3-dithiolans and 1,3-dithians to dihydro-1,4-dithiins and dihydro-1,4-dithiepins, respectively, using phenyl selenenyl chloride in methylene chloride is described. A mechanism involving sulphenyl chloride derivatives as intermediates is proposed.

Preparation of 1λ4,2,4-benzothiadiazines from N-arylbenzamidines

N-Arylbenzamidines react with sulphenyl chlorides and N-chlorosuccinimide to give the cyclic sulphimides, 1λ4,2,4-benzothiadiazines (7), as the major products. Two examples of the analogous 1λ4,2,4-benzoselenadiazine system (8) have been prepared by a similar route. When the ortho-positions of the N-aryl group are blocked, or when an arylsulphenamide is used in place of the sulphenyl chloride in the preparation, the open-chain sulphimides (1) are isolated, but 4,4′-thiobismorpholine gives 1-morpholino-1λ4,2,4-benzothiadiazines (2) as the major products.

Addition of 4-chlorobenzenesulphenyl chloride to 3-methylbut-1-yne, hex-1-yne, and phenylacetylene: isomerization and hydrolysis of the adducts

The addition of (4-ClC6H4SCl, (2), to RCHCH, (1; R = Pri, Bun), gives (E)-4-ClC6H4(R) C = C(H) Cl, (E)-(3), and (E)-4-ClC6H4(H) CC (R) Cl, (E)-(4) in a fixed ratio; the addition to (1; R = Ph) gives regiospecifically (E)-(3; R = Ph) in ethyl acetate, but different proportions of (E)-(3) and (E)-(4)(R = Ph) in chloroform, sym-tetrachloroethane, and acetic acid. With an excess of the sulphenyl chloride (2), (E)-(3) and (E)-(4) isomerize to (Z)-(4)(same R). The sulphuric-acid catalysed hydrolysis of (E)-(3; R = Pri,Bun, Ph) gives α-chloroketones RCOCH2Cl (5)(same R). The (E)-(4) isomers do not hydrolyse.

Sulphur substituted organotin compounds : IX. Formation of [(3-chloro-4- o-nitrophenylthio)butyl]-triphenyltin, Ph 3SnCH 2CH 2CHClCH 2SC 6H 4NO 2- o, from reaction of 4-butenyltriphenyltin and o-nitrobenzenesulphenyl chloride

Reaction of the sulphenyl chloride, o-NO 2C 6H 4SCl, with Ph 3SnCH 2CH 2CHCH 2 occurs to give the adduct, Ph 3SnCH 2CH 2CHClCH 2SC 6H 4NO 2- o. In contrast, no adduct is formed with the more reactive, p-MeC 6H 4SCl. Instead, and as reported previously with Bu 3SnCH 2CH 2CHCH 2, the cyclopropylmethyl aryl sulphide is obtained. The adduct is thermally stable, and reacts with I 2 and HgCl 2 to give phenyld-tin cleaved products, Ph 2SnXCH 2CH 2CHClCH 2SC 6H 4NO 2- o (X = I or Cl).

Control of regioselectivity in the addition of sulphenyl chlorides to 3,3-dimethylbutyne (t-butylacetylene) as a method for differential functionalization of triple bonds

Methanesulphenyl chloride and toluene-p-sulphenyl chloride react with 3,3-dimethylbutyne to give regio- and stereo-specifically (E)-1-chloro-3,3-dimethyl-2-methylthiobut-1-ene (3a) and (E)-1-chloro-3,3-dimethyl-2-p-tolylthiobut-1-ene (3b). trans–cis-Acid-catalysed isomerization of (3a) and (3b) may occur. Sulphenyl chlorides catalyse the conversion of (3a) and (3b) into (Z)-2-chloro-3,3-dimethyl-1-methylthiobutene (4a) and (Z)-2-chloro-3,3-dimethyl-1-p-tolylthiobutene (4b) respectively. The hydrolysis of compounds (3) and (4) affords 1-chloro-3,3-dimethylbutan-2-one (5) and 2-chloro-3,3-dimethylbutanal (6).

Chlorine exchange in ArSCl and its drastic acceleration by the o-NO 2 group

Exchange process ArSCl + Li 36Cl ▪ ArS 36Cl + LiCl occurs rapidly only for the sulphenyl chlorides, containing o-NO 2 group. This finding was rationalized by postulating a sulphurane structure due to participation of the o-NO 2 group.

Stereocontrolled addition of some sulphenyl halides to bicyclo[3.2.0]-hept-2-en-6-ones and modification of the adducts

The bicycloheptenones (1) and (2) reacted with the sulphenyl chlorides (13)–(15) in a highly regioselective manner to give the corresponding adducts (3)–(8) in 77–92% yield. m-Chloroperoxybenzoic acid oxidation of the ketone (5) led to products (9), (10), (22), and (23) resulting from oxidation at sulphur and/or Bayer–Villiger ring expansion. The corresponding dichloroketone (8) suffers oxidation at sulphur only to give the sulphoxide (11) and the sulphone (12). The 7,7-dichlorobicyclohepten-6-one (8) yielded tetra-substituted cyclopentane derivatives (18)–(21) of defined stereochemistry on addition of methanol or piperidine across the C6–C7 bond.

Stereochemistry of the acyclic phosphono- and phosphino-thiocyanide isomerisation into corresponding isothiocyanidates : Synthesis of optically active thiocyanidates > P(O)SCN isothiocyanidates > P(O)NCS, isocyanidates > P(O)NCO and related phosphorylated derivatives of carbonic acid

Optically active t-butylphenylphosphinothiocyanidate ButPhP(O)SCN 3 and t-butyl-O-methyl-phosphonothiocyanidate But(MeO)P(O)SCN 7 have been prepared by condensation of the corresponding sulphenyl chlorides > P(O)SCl with trimethylsilylcyanide and isomerised into optically active t-butyl-O-methyl-phos-phonoisothiocyanidates But(MeO)P(O)NCS 8. Chirality at P in and the optical purity of the chiral phosphino (phosphono) thiocyanidates and isothiocyanidates have been determined by chemical correlations. It has been demonstrated that the thiocyanate ion and amine catalysed thiocyanidate-isothiocyanidate isomerisation > P(O)SCN → > P(O)NCS occurs stereospecifically with inversion of configuration at the P center. This result can be rationalized by postulation of a phosphorane intermediate, formed by nucleophilic attack of the SCN- anion on phosphorus, in which thiocyanate and isothiocyanate groups occupy apical positions. In connection with these studies a number of novel optically active phosphorylated derivatives of carbonic acid, > P(O)NHCSNHR, > P(O)NCCl2, > P(O)NCO and > P(O)NHCOOBut, have also been synthesised.

Electrophilic additions to allenes. VI. The role of steric versus electronic effects in the reactions of arenesulphenyl halides with allenes

The role of steric and electronic effects during the rate and product determining steps for the addition of arenesulphenyl chlorides to 1,3-disubstituted allenes has been briefly examined. Both effects appear to be generally of minimal importance during the rate determining step. The available rate data indicate the presence of little, if any, build up of positive charge on sulphur. These results are interpreted in terms of an SN2 attack on bivalent sulphur leading to an alkylidenethiiranium ion intermediate. Steric effects are of greater importance in the product determining step, particularly when the sulphenyl chlorides possess two bulky ortho substituents, as in the case of 2,4,6-triisopropylbenzenesulphenyl chloride.

Electrophilic cleavage of cyclopropanes. II. Concerning the effect of increasing electron demand upon the product-determining transition state in the reaction of 4-substituted-2-nitrobenzenesulphenyl chlorides and benzenesulphenyl chlorides with tetracyclo[3.2.0.02,7.04,6]heptane (quadricyclene)

The effect of increasing electron demand upon the product-determining transition state in the reaction of arenesulphenyl chlorides with tetracyclo[3.2.0.02,7.04,6]heptane has been investigated. As the electron donating ability of the remote substituents on the phenyl ring of the sulphenyl chloride is varied from nitro to methoxy the relative proportion of adducts derived from edge-on attack is found to increase relative to that of adducts derived from corner attack. An ortho-nitro group was found to lead to a stabilizing interaction only in the case of 2,4-dinitrobenzenesulphenyl chloride. A mechanism involving the competition between the two conceptual modes of approach is suggested.

ADDITION OF SULPHENYL CHLORIDES TO ACETYLENES. STRUCTURE OF THE INTERMEDIATE

Abstract Sulphenyl chlorides react in sulphur dioxide with acetylenes to give thiirenium chlorides 1 which lead to the final adducts 2.

γ-Sulphenylation of αβ-unsaturated aldehydes, ketones, and esters: the use of O-silylated dienolates

Phenyl sulphenyl chloride is a γ-selective electrophile in its reaction with O-silylated dienolates.

New method for increasing of effective electrophilicity of weak electrophiles in addition reactions. Rearrangements and cis-addition in reactions of sulphenyl chlorides with norbornene and dimethoxybenzonorbornadiene

The addition of RSC1 to norbomene and dimethoxybenzonorbornadiene can proceed with Wagner-Meerwein rearrangement. These addition reactions can also undergo a “doping-effect” which increases the effective electrophilicity of sulfenyl chlorides. Addition of ArSCI to dimethoxybenzonorbornadiene can proceed partially with formation of cis-adduct ( 13a) and of inverted trans-adduct ( 12b). Evidence for the ion-pair mechanism and important mechanistic and stereochemical consequences are discussed.

The addition of 2,4-dinitrobenzenesulphenyl chloride to 1,3-disubstituted allenes: a reexamination

The reaction of 2,4-dinitrobenzenesulphenyl chloride with eight alkyl 1,3-disubstituted allenes in methylene chloride solution has been investigated. In contrast to earlier reports, attack by sulphur is found to occur exclusively at the central allenic carbon. The direction of approach of sulphenyl chloride leads preferentially to the formation of the E isomers in accord with the concept of steric approach control. The ratio of E to Z alkene is found to increase as the bulk of the substituent group cis to the arylthio group increases. We observe, however, very little regioselectivity with respect to which of the mutually perpendicular π bonds of the allene system is attacked, suggesting the presence of an effective mechanism for transmission of inductive effects to the more distant double bond.

Polymer modification and synthesis using sulphenyl derivatives. Part 8. Addition of arylsulphenyl chlorides to polyisoprene

Toluene-p-sulphenyl chloride reacts smoothly with cis-1,4-polyisoprene (PIP) in various proportions, but the resulting adducts decompose spontaneously via loss of hydrogen chloride. From an examination of model compounds and of the adducts of PIP with other sulphenyl chlorides, it is concluded that decomposition results from the saturation of successive double bonds along the polymer chain. The extent of decomposition indicates a high degree of regioselectivity in the original addition reaction. Some light is shed on the mechanisms of sulphenyl chloride additions to olefins and of the decomposition of aryl ω-halogenoalkyl sulphides.