Intramolecular ring opening of a 2,3‐epoxy alcohol by a xanthate anionic center; stereospecific preparation of 2‐mercapto‐1,3‐diol units

Abstract

ABSTRACT

Rearrangement of 2,3-Epoxy Alcohol Dimethylthiocarbamate Derivatives. Synthesis of 2,3-Epithio Alcohol Derivatives under Mild Conditions

“…The reduction of the epithio carbamate 7a with lithium aluminum hydride in Et 2 O at −78 °C afforded the known epithio alcohol 9a in 84% yield (er 93:7) contaminated with a small amount of (2 E )-5-phenylpent-2-en-1-ol (>10%). The optical rotation of this product ([α] 22 D +125.0 ( c 1.0, CHCl 3 )) corresponded to that reported previously . Therefore, on the route from 5a to 9a , the inversion of configuration at both stereogenic centers has occurred.…”

“…The optical rotation of this product ([R] 22 D þ125.0 (c 1.0, CHCl 3 )) corresponded to that reported previously. 15 Therefore, on the route from 5a to 9a, the inversion of configuration at both stereogenic centers has occurred. Reduction of 8a with lithium aluminum hydride under similar conditions led to a mixture of products.…”

Synthesis and applications of the sulfur containing analogues of cyclic carbonates

“…21a). 57 The formation of the alkoxide-epoxide intermediate after the addition of NaH followed by the reaction with CS 2 resulted in a moderate final product yield of 44%. As was previously mentioned for the related 5-membered dithiocarbonate analogue, the mechanism proceeded through an acid–base reaction and a subsequent xanthate migration step.…”

“…10a and b). 56,57 At low temperatures, chemo-and stereo-selective control over the final products was observed. Starting from primary or secondary epoxyalcohols the five-membered 1,3-oxathiolane-2-thiones could be Organic & Biomolecular Chemistry Review selectively obtained, with the alcohol group being transposed from the terminal to internal position or vice versa.…”

Applications of Cyclic Sulfates ofvic-Diols: Synthesis of Episulfides, Olefins, and Thio Sugars

“…The synthesis of episulfides generally involves the previous transformation of the diol into the corresponding epoxide and opening with thiocyanate ions or with thiourea, − which are the most common reagents used for this transformation. A recently described method for the synthesis of thiiranes involves a previous transformation of allylic alcohols into cyclic xanthates. − Olefins can be obtained from vic -diols by a variety of different methods. , For example, direct conversion of vic -diols into alkenes is possible by treatment with tungsten reagents, titanium metals, , Me 3 SiCl−NaI, Ph 3 P−imidazole−I 2 , and PBr 3 −CuBr−ether followed by zinc powder − bisdithiocarbonates, cyclic thionocarbonates, − oxiranes, − episulfides, ,− cyclic orthoformiates, , and cyclic phosphates, phosphoroamidates, − and sulfates. , …”