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Synthesis of Δ 3 ‐1,3,4‐Telluradiazolines by Reaction of Fenchone Hydrazone with Tellurium Tetrachloride: Mechanistic Insight into Twofold Extrusion
Author(s) -
Okuma Kentaro,
Yahata Shuhei,
Munakata Kazunori,
Nagahora Noriyoshi,
Shioji Kosei,
Ishikawa Ryuta,
Yamada Yuji
Publication year - 2016
Publication title -
chemistryselect
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.437
H-Index - 34
ISSN - 2365-6549
DOI - 10.1002/slct.201601252
Subject(s) - hydrazone , chemistry , extrusion , thermal decomposition , stereoselectivity , tellurium , yield (engineering) , selenium , derivative (finance) , organic chemistry , medicinal chemistry , materials science , metallurgy , catalysis , economics , financial economics
The reaction of (‐)‐fenchone hydrazone with TeCl 4 and DBU gave two isomers of Δ 3 ‐1,3,4‐telluradiazoline ( syn ‐ and anti ‐forms). Thermolysis of isolated anti ‐Δ 3 ‐1,3,4‐telluradiazoline gave chiral ( E )‐1,1’,3,3,3’,3’‐hexamethyl‐2,2’‐binorbornylidene with perfect stereoselectivity in 93 % yield, which clearly showed that the reaction proceeded through a twofold extrusion process. On the other hand, thermolysis of an anti ‐selenium derivative gave a mixture of E ‐ and Z ‐alkenes along with selenofenchone, suggesting that 1,3‐dipolar retrocyclization proceeded along with twofold extrusion.