122069-04-9Relevant articles and documents
Cycloadditions, 17. - Influence of Methyl and Phenyl Groups in the Allenic ω-Position on the Thermally Induced Isomerizations of N-allenecarboxamides
Schlindwein, Hans-Juergen,Himbert, Gerhard
, p. 2331 - 2340 (2007/10/02)
The N-(2-hetarylmethyl)-1,2-alkadienecarboxamides 9a-q were synthesized by the ylide route, and their readiness to participate in the intramolecular Diels-Alder reaction was studied.Whereas the pyrrole derivatives 9p and 9q and the thiophene derivative 9o without directly bonded phenyl nuclei only decompose, the thiophene allenes 9m and 9n form the "normal" tricycles 12a and 12b by reaction of their amide phenyl nucleus (R1 = Ph).In all N-furfurylallenecarboxamides 9a-l the furan nucleus is involved in the intramolecular Diels-Alder reaction, irrespective of the amine substituent R1.The furan nucleus reacts in all cases with the terminal allenic double bond to form the oxatricycles 10a-l containing a six-membered lactam moiety.Reaction with the first allenic double bond (formation of 11c,d, and g) only takes place, when the reaction with the other double bond is slowed down by one or two methyl groups in the ω-position and the formation of 11 is not prevented by a methyl group in the furan 5-position. - Key Words: Diels-Alder reactions, intramolecular / Allenecarboxamides, N-(hetarylmethyl)-
