Thionyl chloride with epoxides

Preparation of sulfites of jS-halo alcohols by reaction of thionyl chloride with a 1,2-epoxides [39]. (See Procedure 3-1.)... 

The synthetic route of sulfite-linked cycloaliphatic epoxy resin is presented in Figure 8.13 [38]. The synthesis of intermediate is achieved via the nucleophilic substitution reaction of thionyl chloride with cyclohex-3-enyl-1-methanol. Subsequently, Epo-S is obtained by epoxidation with OXONE oxidant. Epo-S is liquid at room temperature which is favorable for the underfilling encapsulation for high-density electronic packaging technologies such as flip chip plastic ball grid array (FC-PBGA) and MCM. 

Special cases concerning the reactivity of intermediate 331 with electrophiles involve the use of A -silylimine or epoxides. In the first case, aminoalcohol 333 was prepared, which was easily cyclized (thionyl chloride followed by basic treatment) to the corresponding substituted tetrahydroisoquinoline 334 (Scheme 98) . ... 

In the event, iodolactonization of the carboxylate salt derived from the ester 458 afforded 459, and subsequent warming of the iodo lactone 459 with aqueous alkali generated an intermediate epoxy acid salt, which suffered sequential nucleophilic opening of the epoxide moiety followed by relactonization on treatment with methanol and boron trifluoride to deliver the methoxy lactone 460. Saponification of the lactone function in 460 followed by esterification of the resulting carboxylate salt with p-bromophenacylbromide in DMF and subsequent mesylation with methanesulfonyl chloride in pyridine provided 461. The diazoketone 462 was prepared from 461 by careful saponification of the ester moiety using powdered potassium hydroxide in THF followed by reaction with thionyl chloride and then excess diazomethane. Completion of the D ring by cyclization of 462 to the keto lactam 463 occurred spontaneously on treatment of 462 with dry hydrogen chloride. 

The most widely used method for the preparation of 1,3,2-dioxathiolane. Y-oxides (cyclic sulfites) 65 bearing C-linked substituents is the reaction of the corresponding 1,2-diols with thionyl chloride in presence of pyridine or Et3N (Scheme 18). More reactive 1,3,2-dioxathiolane. Y,.Y-dioxidcs (cyclic sulfates) 66 are usually obtained by oxidation of sulfites 65 with sodium periodate, which is mediated by mthenium tetroxide generated in situ from a catalytic amount of ruthenium trichloride. Numerous derivatives 65 and 66 were obtained via this approach and its modifications for further transformations, mostly as the synthetic equivalents of epoxides <1997AHC89, 2000T7051> (see also Sections 6.05.5 and 6.05.6, and Tables 1-7). 

Cyclic sulfates provide a useful alternative to epoxides now that it is viable to produce a chiral diol from an alkene. These cyclic compounds are prepared by reaction of the diol with thionyl chloride, followed by ruthenium-catalyzed oxidation of the sulfur (Scheme 9.26).166 This oxidation has the advantage over previous procedures because it only uses a small amount of the transition metal catalyst.167168... 

Unlike epoxides, these five-membered heterocyclics have received scant attention from organic chemists. But the recent catalytic asymmetric dihydroxylation of alkenes (14, 237-239), which is now widely applicable (this volume), and the ready access to optically active natural 1,2-diols has led to study of these compounds, including a convenient method for synthesis. They are now generally available by reaction of a 1,2-diol with thionyl chloride to form a cyclic sulfite of a 1,2-diol, which is then oxidized in the same flask by the Sharpless catalytic Ru04 system, as shown in equation I.1... 

The corresponding 9,1 l-dioxa-10-thiahomoprostanoid 263 was synthesized by reaction of the diol 258 with thionyl chloride. When the reaction with thionyl-chloride was carried out with the erythro diol 264 the isomeric 9,1 l-dioxa-10-thiahomoprostanoid 265 with cis side chains was obtained. The 9,11-dithiahomo-prostanoid 267 was prepared by reaction of the epoxide 266 with potassium methyl xanthate. 

The diols (97) from asymmetric dil droxylation are easily converted to cyclic sii e esters (98) and thence to cyclic sulfate esters (99).This two-step process, reaction of the diol (97) with thionyl chloride followed by ruthenium tetroxide catalyzed oxidation, can be done in one pot if desired and transforms the relatively unreactive diol into an epoxide mimic, ue. the 1,2-cyclic sulfate (99), which is an excellent electrophile. A survey of reactions shows that cyclic sulfates can be opened by hydride, azide, fluoride, thiocyanide, carboxylate and nitrate ions. Benzylmagnesium chloride and thie anion of dimethyl malonate can also be used to open the cyclic sulfates. Opening by a nucleophile leads to formation of an intermediate 3-sidfate aiuon (100) which is easily hydrolyzed to a -hydroxy compound (101). Conditions for cat ytic acid hydrolysis have been developed that allow for selective removal of the sulfate ester in the presence of other acid sensitive groups such as acetals, ketals and silyl ethers. 

Hydroxy selenides prepared by the reaction of epoxides with selenophenol and methanol are converted to alkenes upon treatment with thionyl chloride/triethylamine in methylene chloride (equations 33... 

The dimethylformamide-thionyl chloride complex reacts rapidly with steroid alcohols to give formyl esters in almost quantitative yield and with retention of configuration it converts even tertiary alcohols into their formyl esters. It reacts with an epoxide to give the l-formyloxy-2-chloro compound or the 1,2-dichloro compound. ... 

Hydrolysis of each acid fluoride fraction and redistillation of the carboxylic acids allowed separation of mono- from dicarboxylic acids (Table III). Thus, the 1 1 dicarboxylic acid and the monocarboxylic acid formed from three molecules of hexafluoropropylene epoxide were isolated from the 1 1 oligomer acid fluoride fraction shown in Table II. The acids were converted to acid chlorides in high yields (about 90%) by prolonged refluxing with thionyl chloride (Table IV). A trace of pyridine was added as a catalyst. 

Raphael, the iodoaromatic (227) is first coupled with the acetylenic alcohol (228) in the presence of Pd° leading to the central intermediate (229). Meyer-Schuster rearrangement of (229) in the presence of methane sulphonic acid then gave rise to (231) presumably via the initially formed ketone (230). Reduction of (231) followed by dehydration next led to (232), which was elaborated to virantmycin, via epoxidation, reduction, deprotection, treatment with thionyl chloride, and finally ester hydrolysis. 

Acid 121 can be converted to acid chloride 126 with either thionyl chloride [46] or oxalyl chloride [49]. Friede 1-Crafts acylation on m-difluorobenzene with 126 gives the (i )-chlor-oketone 127 (97% ee) in 80% overall yield from 121. Epoxidation of 127 affords 128 with > 95% diastereoselectivity. Reaction of the epoxide with triazole furnishes ra 5-epoxide (2S, 35)-129, an isomer of an important intermediate for the preparation of a class of triazole antifungal agents (Scheme 19). 

Cyclic sulfates 540a-c are conveniently prepared in good yields by a two-step, one-pot transformation of the appropriate diester la or lb with thionyl chloride followed by ruthenium tetroxide oxidation. They behave like epoxides in that they simultaneously activate and protect adjacent functionalized carbon atoms from nucleophilic attack. As a consequence of their cyclic nature, they render competing elimination processes stereochemically unfavorable [175]. 

When the epoxide (presumably the a-form, XXXIV) is reduced with lithium aluminum hydride in ether-benzene and the reaction product reacetylated with acetic anhydride-pyridine, there is formed an 0,0 -diacetyl-W-ethylhydroxydihydroveratramine (XL), which readily loses water in contact with thionyl chloride-pyridine to generate an 0,0 -diacetyl-iV-ethylveratramine (XLI). During this reduction there is also formed a product which on reacetylation proved to be 0,0 -diacetyl-iV-ethyldihydroxydihydroveratramine (XLII). Its structure is uncertain but it appears to be formed by hydrolytic rather than reductive cleavage of the epoxide ring (42). 

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