1,3‐Oxathiolan‐Synthese: Spirocyclische 1,3‐Oxathiolane aus der <i>Lewis</i>‐Säure‐katalysierten Umsetzung von cyclischen Trithiocarbonaten und Oxiranen

Oremus, V.; Linden, Anthony; Heimgartner, Heinz

doi:10.1002/hlca.19910740714

Cited by 22 publications

(16 citation statements)

References 15 publications

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“…On the other hand, 2-phenyloxirane is attacked mainly at C(2) under inversion of the configuration to yield the 4-phenyl-substituted products. Similar reactions have been observed with 1,3-thiazole-5(4H)-thiones [7] [8], with cyclic trithiocarbonates [9], and with a rhodanine derivative [10].…”

supporting

confidence: 74%

Regio‐ and Stereoselective 1,3‐Oxathiolane Formation in the Reaction of Thiolactones with Optically Active Oxiranes

Fu¹,

Linden²,

Heimgartner³

2004

Helvetica Chimica Acta

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The reactions of 3H-isobenzofuran-1-thione (1) with (S)-2-methyloxirane (2) and (R)-2-phenyloxirane (6) in the presence of SiO2 in anhydrous CH2Cl2 led to two pairs of diastereoisomeric spirocyclic 1,3-oxathiolanes, i.e., 3 and 4 with a Me group at C(5'), and 7 and 8 with a Ph group at C(4'), respectively (Schemes 2 and 3). In both cases, 3H-isobenzofuran-1-one (5) was formed as a main product. The analogous reactions of 3,4-dihydro-2H-[1]benzopyran-2-thione (9) and 3,4,5,6-tetrahydro-2H-pyran-2-thione (14) with 2 and 6 yielded four pairs of the corresponding diastereoisomeric spirocyclic compounds 10 and 11, 12 and 13, 15 and 16, and 18 and 19, respectively (Schemes 4 -7). In the reaction of 14 with 6, the 1,3-oxathiolane 20 with a Ph group at C(2) was also formed. The structures of 3,7,8,10,19, and 20 were established by X-ray crystallography (Figs.1-4). In contrast to the thiolactones 1, 9, and 14, the thioesters 21a-21d did not react with (R)-2-phenyloxirane (6) either in the presence of SiO2 or under more-drastic conditions with BF3 . Et2O or SnCl4 (Scheme 8). The results show that spirocyclic 1,3-oxathiolanes can be prepared from thiolactones with oxiranes. The nucleophilic attack of the thiocarbonyl S-atom at the SiO2-activated oxirane ring proceeds with high regio-and stereoselectivity via an SN2-type mechanism.

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confidence: 74%

Regio‐ and Stereoselective 1,3‐Oxathiolane Formation in the Reaction of Thiolactones with Optically Active Oxiranes

Fu¹,

Linden²,

Heimgartner³

2004

Helvetica Chimica Acta

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“…configuration, leading to the intermediate zwitterion A [5b] [16]. Ring closure gives the spirocyclic 1,3-oxathiolane B, which rearranges to yield the new zwitterion C. The latter then decompose to give the isolated product (S)-15 and 1-methylpyrrolidin-2-one (14b).…”

Section: Methodsmentioning

confidence: 99%

“…In contrast to the reaction of 14a and (R)-11, the S-atom of 14a attacked preferably at the less hindered C(3)-atom of (R)-16b to give the zwitterionic intermediate D with retention of the configuration (see also [5b] [16]). …”

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

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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“…For example, 1,3-dithiolane-2-thione (1) and 2-ethyloxirane (2a) in 1,2-dichloroethane and TiCl 4 at -20°C gave the spirocyclic 1,3-oxathiolanes 3a and 4a (R = Et) in a ratio of 15:1 (Scheme 1). On the other hand, the ratio 3b/4b (R = Ph) was determined to be 1:20 [2]. …”

Section: Introductionmentioning

confidence: 98%

“…cited in [1]). Some years ago, we discovered that the Lewis acid-catalyzed reaction of oxiranes with 4,4-disubstituted 1,3-thiazole-5(4H)-thiones and trithiocarbonates, respectively, offers another convenient access to 1,3-oxathiolanes [1,2]. For example, 1,3-dithiolane-2-thione (1) and 2-ethyloxirane (2a) in 1,2-dichloroethane and TiCl 4 at -20°C gave the spirocyclic 1,3-oxathiolanes 3a and 4a (R = Et) in a ratio of 15:1 (Scheme 1).…”

Section: Introductionmentioning

confidence: 99%

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

Fu¹,

Blagoev²,

Linden³

et al. 2005

ChemInform

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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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1,3‐Oxathiolan‐Synthese: Spirocyclische 1,3‐Oxathiolane aus der Lewis‐Säure‐katalysierten Umsetzung von cyclischen Trithiocarbonaten und Oxiranen

Cited by 22 publications

References 15 publications

Regio‐ and Stereoselective 1,3‐Oxathiolane Formation in the Reaction of Thiolactones with Optically Active Oxiranes

Regio‐ and Stereoselective 1,3‐Oxathiolane Formation in the Reaction of Thiolactones with Optically Active Oxiranes

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

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

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