Trimethylsilyl isothiocyanate

Reactions of Heterocyclic N-Oxides with Trimethylsilyl Cyanide, Trimethylsilyl Azide, Trimethylsilyl Isothiocyanate, and Trimethylsilyl Halides... 

An interesting approach for the synthesis of spiro-OZTs and oxazine-2-thiones in D-psicofuran and D-fructopyran series involved as a key-step the reaction with trimethylsilyl isothiocyanate, azide or cyanide.8 The reaction mechanism is similar to the one described above—after nucleophilic attack on the anomeric position, the formed isothiocyanate undergoes spontaneous cyclization to afford the corresponding spiro-thionocarbamate. 

In a different study, anthracene, phenanthrene, perylene 93 (Fig. 31), and 2,7-di-tert-butylpyrene underwent regioselective oxidative-substitution reactions with iodine(III) sulfonate reagents in dichloromethane to give the corresponding aryl sulfonate esters. The use of [hydroxy(tosyloxy)iodo]benzene, in conjunction with trimethylsilyl isothiocyanate, led to thiocyanation of the PAH nucleus. 

Exposure of alkenes to a combination of 4 and trimethylsilyl isothiocyanate leads to the formation of 1,2-dithiocyanates [Eq. (8)] [28]. The reaction involves the formation of bis(thiocyanato)-A3-iodane by a ligand exchange. The decomposition of this iodane leads to the formation of thiocyanogen, which in turn undergoes the anti electrophilic addition to olefins. 

Admixture of BAIB with two equivalents of trimethylsilyl isothiocyanate in dichloromethane leads to the rapid formation of thiocyanogen and iodoben-zene, presumably via [bis(thiocyanato)iodo]benzene (Scheme 10) [32]. The addition of alkenes to such solutions affords vzcmaZ-dithiocyanatoalkanes. Cyclohexene and its 1-methyl analog were converted exclusively to the transadducts under these conditions, while dihydropyran gave a 1 1 mixture of cis-and trans-isomers. 

Kimura, K., K. Katada, and S. H. Bauer An Electron Diffraction Study of Trimethylsilyl Isothiocyanate and Trimethylsilyl Isocyanate. J. Amer. chem. Soc. 88, 416—420 (1966). 

Trimethylsilyl isothiocyanate reacts with COFj at 50 "C in an autoclave to produce CO(NCS)F in quantitative yield [2111a] ... 

Trimethylsilyl isothiocyanate [2290-65-5] M 131.3, m -33 , b 142.6-143.l /759mm, 143.8 /760mm, n 1.4809. The H NMR spectrum should have only one peak if not purify it by repeated fractionation in an all-glass system using a 50cm (4mm internal diameter) column without packing. [Anderson J Am Chem Soc 69 3049 1947, Feher Bliimcke Chem Ber 90 1934 1957, Neidleim Hege Synthesis 51 1975, Beilstein 4 III 1861,4 IV 4011.]... 

Catalysed aerobic epoxidation of the styrene-cobalt complex, followed by the addition of trimethylsilyl isothiocyanate, yields 4-phenyloxazolidine-2-thione 123 <96TL7315>. The 4-substituted 2-oxazolidinone 124 undergoes a "chromium Reformatsky" reaction with aldehydes RCHO (R = i-Pr or Ph) in the presence of chromium(ll) chloride and lithium iodide to give mainly the unusual anti-aldol products 125 in excellent dia,stereomeric excess and yield <97TL4,387>. 

If a mixture of 2,4,6-tri(l-methylethyl)-1,3,5-trioxane, trimethylsilyl isothiocyanate, and SnCl2 is stirred for 1.5 h at room temperature, 70% of the corresponding isothiocyanato substituted ether 0[CH(CH3)NCS]2 is obtained. 2,4,6-Trimethyl-l,3,5-trioxane was converted also into bis(l-isothiocyanatoethyl) ether in similar yield. However, 1,3,5-trioxane was recovered quantitatively under the same reaction conditions <1987BCJ2289>. 

A similar reaction of (diacetoxyiodo)benzene with alkenes and trimethylsilyl isothiocyanate in dichloromethane affords 1,2-dithiocyanates 540 in moderate yield (Scheme 3.212). Cyclic alkenes, such as cyclohexene and 1-methylcyclohexene, react with this reagent system stereoselectively with the formation of the respective trans-aMuct [598,599],... 

The reaction of polycyclic aromatic hydrocarbons with [hydroxy(tosyloxy)iodo]benzene in the presence of trimethylsilyl isothiocyanate leads to the regioselective thiocyanation of an arene nucleus, as illustrated by the reaction of anthracene shown in Scheme 3.213 [274],... 

This reaction has been extended to the reaction of terminal amino acids with thiocyanic acid7b,9 developed initially by Johnson ) and trimethylsilyl isothiocyanate for the formation of thiohydantoin. In addition, 12 N HCl and acetohydroxamate have been used to cleave the 2-thiohydantoin from the peptide chain. 

An ethereal soln. of trimethylsilyl isocyanate added with stirring to a soln. of startg. azirine in ether, then after a few min methanol in ether added slowly - 4-(dimethylamino)-5,5-dimethyl-3-imidazolin-2-one. Y 78%. F.e., also 4-amino-A -2-imidazolinethiones with trimethylsilyl isothiocyanate, s. I. Handke, E. Schaumann, J. Org. Chem. 53, 5298-300 (1988). 

One of the most commonly used methods to obtain 2-amino-l, 3,4-thiadiazolines is the heterocyclization of thiosemicarbazides. An efficient one-pot synthesis of 2-amino-l,3,4-thiadiazoles 125 features the in situ formation of thiosemicarbazides 123 by the reaction of carboxylic acid hydrazides 121 with trimethylsilyl isothiocyanate (TMSNCS) 122, followed by cyclodehydration of thiosemicarbazides 123 under acidic conditions (13RSC6813). 

In the reaction of 3-(dialkylamino)-2//-azirines with trimethylsilyl isothiocyanate the initially formed [2+2] cycloadduct 59 again is transformed into the five-membered ring compound 60, which on treatment with methanol to remove the silyl group is converted into 4-(dialkylamino)imidazoline-2-thiones 61 (yield 26-80... 

A novel chiral imidazoline-substituted phosphoric acid catalyst (274) has been successfully applied for highly enantioselective desymmetrisa-tion of aziridines (273) with trimethylsilyl isothiocyanate (TMSNCS) (Scheme 74). ... 

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