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Intramolecular diels‐alder reactions. XI. Modal selectivity in the syntheses of some parent cyclolignan lactones
Author(s) -
Klemm L. H.,
Tran Vinh Tan,
Olson D. R.
Publication year - 1976
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.5570130410
Subject(s) - chemistry , intramolecular force , selectivity , yield (engineering) , solvent , diels–alder reaction , medicinal chemistry , acetic anhydride , dimethylformamide , lactone , organic chemistry , catalysis , materials science , metallurgy
Ph(C 2 )CH 2 Cl and Ph(C 2 )'CO 2 Na [where (C 2 ) = ‐C=C‐ or trans ‐CH=CH‐, (C 2 )' = ‐C=C‐ or cis ‐CH=CH‐] reacted in refluxing dimethylformamide to yield unsaturated esters Ph(C 2 )'CO 2 ‐CH 2 (C 2 )Ph and/or their intramolecular Diels‐Alder cyclization products (cyclolignan lactones). It was found that modal selectivity for cyclization in DMF sometimes varies from that found previously with acetic anhydride as solvent. Two new parent tetrahydrocyclolignan lactones were synthesized.