Lewis Acid Catalyzed Reactions of Thioketones with 1,2-Epoxycyclohexane and 1,2-Epoxycyclopentane

Blagoev, Milen; Linden, Anthony; Heimgartner, Heinz

doi:10.1002/(sici)1522-2675(19991215)82:12<2316::aid-hlca2316>3.0.co;2-3

Cited by 25 publications

(10 citation statements)

References 14 publications

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“…In some cases, 1,3-dithiolanes and 1,3-dioxolanes are formed in addition to 1,3-oxathiolanes [4,6,7]. For example, the BF 3 -catalyzed reaction of thiobenzophenone (13a) and 1,2-epoxycyclohexane (15) in dichloromethane at -50°C yields 16, 17a, and 17b [6].…”

Section: Methodsmentioning

confidence: 99%

“…For example, the BF 3 -catalyzed reaction of thiobenzophenone (13a) and 1,2-epoxycyclohexane (15) in dichloromethane at -50°C yields 16, 17a, and 17b [6]. It has been shown that 17a and 17b are secondary products, which are formed by decomposition of 16 to give benzophenone and 1,2-epithiocyclohexane and subsequent reaction with oxirane 15 and thiobenzophenone 13a, respectively.…”

Section: Methodsmentioning

confidence: 99%

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Regio- and Stereoselective Formation of 1,3-Oxathiolanes by Reactions of Thiocarbonyl Compounds with Oxiranes

Heimgartner

Blagoev

et al. 2005

Phosphorus, Sulfur, and Silicon and the Related Elements

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Lewis acid-catalyzed reactions of oxiranes with a variety of C=S compounds yield 1,3-oxathiolanes. The ring enlargement of monosubstituted oxiranes occurs regioselectively via cleavage of the O,C(3) bond of alkyl substituted oxiranes and the O,C(2) bond of phenyl oxirane. Furthermore, the reaction proceeds with inversion of the configuration at the center of the nucleophilic attack by the S-atom. The formation of thiocarbonylium ions as intermediates is supported by Wagner-Meerwein-type rearrangements. Enolized thioketones react with oxiranes to give enesulfanyl alcohols, which undergo an acid-catalyzed cyclization to yield 1,3-oxathiolanes. Lewis acid-catalyzed reactions of oxiranes with a variety of C=S compounds yield 1,3-oxathiolanes. The ring enlargement of monosubstituted oxiranes occurs regioselectively via cleavage of the O,C(3) bond of alkyl substituted oxiranes and the O,C(2) bond of phenyl oxirane. Furthermore, the reaction proceeds with inversion of the configuration at the center of the nucleophilic attack by the S-atom. The formation of thiocarbonylium ions as intermediates is supported by Wagner-Meerwein type rearrangements. Enolized thioketones react with oxiranes to give enesulfanyl alcohols, which undergo an acid-catalyzed cyclization to yield 1,3-oxathiolanes. REGIO-AND STEREOSELECTIVE FORMATION OF 1,3-OXATHIOLANES BY REACTIONS OF THIOCARBONYL COMPOUNDS WITH OXIRANES

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Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Regio- and Stereoselective Formation of 1,3-Oxathiolanes by Reactions of Thiocarbonyl Compounds with Oxiranes

Heimgartner

Blagoev

et al. 2005

Phosphorus, Sulfur, and Silicon and the Related Elements

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“…(6) [4b] in 73.7% yield (Scheme 6). On the other hand, heterocyclic thiones containing a neighboring N-atom react with oxiranes, in general, to give thiiranes via a S-transfer reaction [4b] [10].…”

Section: Reaction Of 14a With (R)-2-{[(triphenylmethyl)oxy]methyl}oximentioning

confidence: 99%

“…In some cases, e.g., in the BF 3 -catalyzed reaction of thiobenzophenone with 1,2-epoxycyclohexane (4), in addition to the expected 1,3-oxathiolane 5a, the corresponding 1,3-dithiolane 5b and the 1,3-dioxolane 5c were formed as minor products [6] (Scheme 1). It has been shown that 5b and 5c are secondary products, and a reaction mechanism via the intermediate formation of 1,2-epithiocyclohexane (6) and benzophenone was proposed 2) .…”

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confidence: 99%

Reaction of Optically Active Oxiranes with Thiofenchone and 1‐Methylpyrrolidine‐2‐thione: Formation of 1,3‐Oxathiolanes and Thiiranes

Fu¹,

Linden²,

Heimgartner³

2011

Helvetica Chimica Acta

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The SnCl4‐catalyzed reaction of (−)‐thiofenchone (=1,3,3‐trimethylbicyclo[2.2.1]heptane‐2‐thione; 10) with (R)‐2‐phenyloxirane ((R)‐11) in anhydrous CH2Cl2 at −60° led to two spirocyclic, stereoisomeric 4‐phenyl‐1,3‐oxathiolanes 12 and 13 via a regioselective ring enlargement, in accordance with previously reported reactions of oxiranes with thioketones (Scheme 3). The structure and configuration of the major isomer 12 were determined by X‐ray crystallography. On the other hand, the reaction of 1‐methylpyrrolidine‐2‐thione (14a) with (R)‐11 yielded stereoselectively (S)‐2‐phenylthiirane ((S)‐15) in 56% yield and 87–93% ee, together with 1‐methylpyrrolidin‐2‐one (14b). This transformation occurs via an SN2‐type attack of the S‐atom at C(2) of the aryl‐substituted oxirane and, therefore, with inversion of the configuration (Scheme 4). The analogous reaction of 14a with (R)‐2‐{[(triphenylmethyl)oxy]methyl}oxirane ((R)‐16b) led to the corresponding (R)‐configured thiirane (R)‐17b (Scheme 5); its structure and configuration were also determined by X‐ray crystallography. A mechanism via initial ring opening by attack at C(3) of the alkyl‐substituted oxirane, with retention of the configuration, and subsequent decomposition of the formed 1,3‐oxathiolane with inversion of the configuration is proposed (Scheme 5).

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“…Whereas cyclohexene oxide (63) yields a mixture of 64 and 65, only the corresponding 1,3-dithiolane is obtained in the case of cyclopentene oxide (eq 27). 58 The formation of 1,3-dithiolanes is evidenced to involve the correponding thiirane formed in situ by cleavage of the 1,3-oxathiolane ring. The structures of the products show that the heterocycle is formed with inversion of the configuration of one oxirane C-atom.…”

Section: %mentioning

confidence: 99%

2,2,4,4-Tetramethylcyclobutane-1-one-3-thione

Heimgartner

Mlostoń

2004

Encyclopedia of Reagents for Organic Synthesis

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Lewis Acid Catalyzed Reactions of Thioketones with 1,2-Epoxycyclohexane and 1,2-Epoxycyclopentane

Cited by 25 publications

References 14 publications

Regio- and Stereoselective Formation of 1,3-Oxathiolanes by Reactions of Thiocarbonyl Compounds with Oxiranes

Regio- and Stereoselective Formation of 1,3-Oxathiolanes by Reactions of Thiocarbonyl Compounds with Oxiranes

Reaction of Optically Active Oxiranes with Thiofenchone and 1‐Methylpyrrolidine‐2‐thione: Formation of 1,3‐Oxathiolanes and Thiiranes

2,2,4,4-Tetramethylcyclobutane-1-one-3-thione

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