Intramolekulare Diels‐Alder‐Additionen in 6‐(But‐3‐enyl)‐6‐methyl‐cyclohexa‐2,4‐dien‐1‐on‐Systemen; eine neue Synthese von Twistanderivaten

摘要: Alkylation of the sodium salt mesitol with 2-bromomethyl-buta-1,3-diene (7) in benzene and subsequent refluxing reaction mixture gave 7% 2-methylene-3-butenyl-mesitylether (8), 12% 5-methylene-1,3,8-trimethyl-tricyclo[4,3,1,03,7]-8-decen-2-one (9) 44% 9-methylene-1,3,5-trimethyl-tricyclo[4,4,0,03,8]-4-decen-2-one (10), a twistane derivative. The same procedure, when applied to 2,6-dimethyl-4-methoxyphenol, 73% yield 26:18:54 2,6-dimethyl-4-methoxyphenyl-(2-methylene-3-butenyl)-ether (11), 1,3-dimethyl-8-methoxy-5-methylene-tricyclo[4,3,1,03, 7]-8-decen-2-one (12), 1,3-dimethyl-5-methoxy-9-methylene-tricyclo[4,4,0,03, 8]-4-decen-2-one (13). tricyclic ketones 9 10, or 12 13, were also obtained on heating 8 11 respectively at 176° decane solution. 2,6-dimethylphenol 3-butenylbromide boiling toluene 1,3-dimethyl-tricyclo[4,3,1,03,7]-8-decen-2-one (17) as only product 8% yield. structures derivatives 10 13 well those 9, 17 mainly deduced from spectroscopic data. Furthermore, could be converted 20 22, possessing C2-symmetry. On other hand, compounds asymmetric 18 21.