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Intramolecular ene reactions, III. Diastereoselective formation of cyclohexanes by intramolecular ene reactions of 1,7‐dienes
Author(s) -
Tietze Lutz F.,
Beifuß Uwe
Publication year - 1988
Publication title -
liebigs annalen der chemie
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.825
H-Index - 155
eISSN - 1099-0690
pISSN - 0170-2041
DOI - 10.1002/jlac.198819880404
Subject(s) - chemistry , cyclohexanes , intramolecular force , ene reaction , moiety , yield (engineering) , adduct , knoevenagel condensation , tandem , medicinal chemistry , stereochemistry , organic chemistry , catalysis , materials science , metallurgy , composite material
The 1,7‐dienes 3a–c with a double‐activated enophile moiety undergo thermal and zinc bromide catalyzed intramolecular ene reactions leading to trans ‐1,2‐disubstituted cyclohexanes 4a – c in up to 89% yield, highly diastereoselectively. The synthesis of cyclohexanes from 1,7‐dienes has not been feasible so far in a selective way and with good yields. Reaction of 3d, 3e , and 3f gives mixtures of intramolecular hetero Diels‐Alder adducts, ene and tandem ene products. The 1,7‐dienes 3 are obtained by Knoevenagel condensation of 7‐methyl‐6‐octenal ( 2 ) with acyclic 1,3‐dicarbonyl and analogous compounds 1 .