Thietanes synthesis

The more general methods of thietane synthesis have been reviewed. Table 5 in Section XXXXV gives some examples of the various thietanes prepared. ... 

NMR, 7, 409 Thietane, 2-thioxo-rearrangements, 7, 422 Thietane, triimino-cycloadducts, 7, 433 synthesis, 7, 41 Thietane-2,4-diones synthesis, 7, 435 Thietanes, 7, 403-447 5-amination, 7, 444 basicity, 7, 424 bicyclic... 

The addition of sulfenic acids to olefins207 has been successfully applied in the synthesis of thietanoprostanoids, the thietane analogues of prostaglandin245. The general synthetic scheme is presented in equation 83207. The key step is the thermolysis of either erythro- or (7ireo-2-f-butylsulphinyl-3-vinyl-l-ol (209) to give the corresponding alkenesulfenic acids 210, which cyclize spontaneously to a mixture of stereoisomeric thietane oxides. 

Asymmetric induction and the synthesis of optically active thietane and thiete dioxides can be achieved via the basic strategy depicted above (equation 87), by using optically active enamine in the first (2 + 2) cycloaddition187 (equation 90). [Pg.449]

Chiral thietane dioxides, synthesis of 449 Chiral thiete dioxides, synthesis of 449 Chlorine compounds, as oxidizing agents... 

The preparation and investigation of the thietane oxide system (5a) is largely associated with stereochemical and conformational studies . The investigation of the thietane dioxides (5b) is substantially related to the chemistry of sulfenes , the [2 -I- 2] cycloaddition of which with enamines is probably the method of choice for the synthesis of 5b . The study of the thiete dioxide system (6) evolved, at least in part, from the recognition that the unstable thiete system 183 can be uniquely stabilized when the sulfur in the system is transformed into the corresponding sulfone , and that the thiete dioxide system is very useful in cycloadditions and thermolytic reactions. The main interest in the dithietane oxides and dioxides (7) appears to lie in the synthetic challenge associated with their preparation, as well as in their unique structural features and chemical behavior under thermolytic conditions . ... 

A novel synthesis of isothiazolidines involves sulfonium ylides, formed by the reaction of thietanes and nitrenes <06TL1109>. Exposure of A-(/ -tolylsulfonyl)imino)phenyliodinane 232 with excess of thietanes 231 (5 equiv) in the presence of a catalytic amount of Cu(II)... 

Although sodium sulphide reacts readily with haloalkanes [2] and activated aryl halides (see Chapter 2) [e.g. 3-5] in the presence of a quaternary ammonium catalyst to form symmetrical thioethers (Table 4.1), a major side reaction results in the formation of disulphides owing to the oxidation of the intermediate thiols under the basic conditions. Consequently, little use has been made of this procedure for the synthesis of thioethers [3, 6], but the corresponding reaction of the a,(0-dihaloalkanes to yield cyclic thioethers has proved to be a valuable procedure for the synthesis of thietanes [7] (Table 4.2). The ring closure with the secondary dihaloalkanes is considerably more difficult to effect than is the reaction of the primary dihaloalkanes. 1,3-Dihydrobenzo[c]thiophene (89%) is produced in the reaction of 1,2-bis(bromomethyl)benzene with sodium sulphide (Scheme 4.1) [8]. The direct... 

A. Roy, B. Achari, and S. B. Mandal, An easy access to spiroannulated glyco-oxetane, -thietane and -azetane rings Synthesis of spironucleosides, Tetrahedron Lett., 47 (2006) 3875—3879. 

Application of the enamine-sulfene cycloaddition allowed the synthesis of 78 and 79 from the corresponding a,/l-unsaturated amines and sulfenes. Similarly, using enamine 80, the crystalline morpholino thietane dioxides (81) were produced. Elimination via the N-oxide gave the corresponding thiete dioxide, whereas reduction by LiAlH4 yielded the thietane 82. 

With no major research on the reaction of phosphorus ylides and aliphatic or alicyclic thiones prior to their investigation, Krapcho et where able to elaborate a useful method for the synthesis of the thietane ring system in addition to the preparation of novel types of thiocarbonyl stabilized ylides (Eq. 1). 

Heating of thietanes can often lead to a ring contraction. Thermal treatment (150°C, in vacuo) of the tosylhydrazide salt 213 gives the allene epi-sulfide 214, a unique synthesis for this molecule. The mechanism is suggested to proceed either via the intermediate bicyclobutane ylide 215 or the mesomeric structure 216. Dodson et al. have noticed the rearrangement... 

The reaction of thietanes with electrophilic oxygen will be covered in Section 5.14.4.3 (Synthesis of Derivatives of the Ring Systems). 

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