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Intramolekulare Diels‐Alder‐Additionen in 6‐Methyl‐6‐(penta‐2,4‐dienyl)‐cyclohexa‐2,4‐dien‐1‐on‐Systemen. Vorläufige Mitteilung
Author(s) -
Greuter H.,
Fráter Gy.,
Schmid H.
Publication year - 1972
Publication title -
helvetica chimica acta
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.74
H-Index - 82
eISSN - 1522-2675
pISSN - 0018-019X
DOI - 10.1002/hlca.19720550224
Subject(s) - chemistry , intramolecular force , ether , stereochemistry , derivative (finance) , medicinal chemistry , yield (engineering) , organic chemistry , materials science , financial economics , economics , metallurgy
Thermal rearrangement of trans ‐penta‐2,4‐dienyl mesityl ether ( trans ‐ 1 ) gave, besides trans , cis ‐ 2 and trans , trans ‐ 2 , the homotwistanone derivative 1,3,10‐trimethyl‐tricyclo[5.4.0.0 3,9 ]undeca‐5,10‐dien‐ 2 ‐one ( 3 ) as well as its isomer 1,3,9‐trimethyl‐tricyclo[5.3.1.0 3,8 ]undeca‐5, 9‐dien‐ 2 ‐one ( 4 ). The tricyclic ketones 3 und 4 were shown to be products of intramolecular Diels ‐ Alder addition in the intermediate 2,4,6‐trimethyl‐6‐(penta‐2,4‐dienyl)cyclohexa‐2,4‐dien‐1‐one ( 5 ). Preparation of 2,6‐methyl‐6‐(3‐methyl‐penta‐2,4‐dienyl)‐cyclohexa2,4‐dien‐1‐one ( 6 ) and subsequent heating of 6 in benzene gave the homotwistanone derivative 1,3‐6‐trimethyl‐tricyclo5.4.0.0 3,9 ]undeca‐5,10‐dien‐ 2 ‐one ( 7 ) together with its isomer 1,3,6‐trimethyl‐tricyclo[5.3.1.0 3,8 ]undeca‐5,9‐dien‐2‐one ( 8 ) in good yield.