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Synthesis of spirolactones by 1,3‐dipolar cycloadditions to methyl ( S )‐3‐[( E )‐cyanomethylidene]‐2‐oxotetrahydrofuran‐5‐carboxylate
Author(s) -
Pirc Samo,
Rečnik Simon,
Škof Marko,
Svete Jurij,
Golič Ljubo,
Meden Anton,
Stanovnik Branko
Publication year - 2002
Publication title -
journal of heterocyclic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.321
H-Index - 59
eISSN - 1943-5193
pISSN - 0022-152X
DOI - 10.1002/jhet.5570390227
Subject(s) - diazomethane , chemistry , triethylamine , carboxylate , nitrile , diastereomer , potassium cyanide , medicinal chemistry , acetic acid , 1,3 dipolar cycloaddition , carbanion , cyanide , organic chemistry , cycloaddition , catalysis
Dedicated to Professor Emeritus Miha Tišler on the occasion of his 75th birthday Treatment of methyl ( S )‐5‐[( E )‐(dimethylamino)methylidene]‐2‐oxotetrahydrofuran‐5‐carboxylate ( 2 ) with potassium cyanide in acetic acid gave ( S )‐5‐[( E )‐cyanomethylidene]‐2‐oxotetrahydrofuran‐5‐car‐boxylate ( 3 ), which was used as chiral dipolarophile in 1,3‐dipolar cycloadditions. Reactions of 3 with diazomethane ( 4 ) and nitrile oxides 5a‐c afforded spirolactones 6–8 in 24‐34% diastereomeric excess, while with diazomethane ( 4 ) in the presence of triethylamine, methyl 3‐cyanomethyl‐2‐methoxyfuran‐5‐carboxylate ( 12 ) was obtained.