One pot diastereoselective synthesis of new chiral spiro-1,3,4-thiadiazoles and 1,4,2-oxathiazoles from (1R)-thiocamphor

✍ Scribed by Amal Feddouli; Moulay Youssef Ait Itto; Aïssa Hasnaoui; Didier Villemin; Paul-Alain Jaffrès; Jana Sopkova-De Oliveira Santos; Abdelkhalek Riahi; FranÇOis Huet; Jean-Claude Daran

• Publisher: Journal of Heterocyclic Chemistry
• Year: 2004
• Tongue: English
• Weight: 200 KB
• Volume: 41
• Category: Article
• ISSN: 0022-152X
• DOI: 10.1002/jhet.5570410513

✦ Synopsis

Abstract

Herein we report an efficient one pot synthesis of new chiral 4,5‐dihydro‐4‐arylspiro[1,3,4‐thiadiazole]‐5,2′‐camphane‐2‐carboxylic acid ethyl esters 5–7 and 4,5‐dihydro‐3‐arylspiro[1,4,2‐oxathiazole]‐5,2′‐camphane 11–13, using 1,3‐dipolar cycloaddition of nitrilimines 2–4 and nitrile oxides 8–10 to (1__R__)‐thiocamphor 1 respectively. The structure of the newly prepared 1,3,4‐thiadiazoles 5–7 (obtained as pure diastereoisomers) were fully established via spectroscopic analysis and X‐ray structural analysis which proved the absolute configuration of the C5 spiranic carbon to be (R). NMR spectral analysis were also very useful to show the new 1,4,2‐oxathiazoles 11–13 are mixtures of two (5__R__)/(5__S__) diastereoisomers with the ratio 6:4,7:3 and 6:4 respectively.