86791-29-9Relevant academic research and scientific papers
Reactions of Vinylogous Oxycarbenes with Methanol
Hoemberger, Guenter,Kirmse, Wolfgang,Lelgemann, Rudolf
, p. 1867 - 1869 (2007/10/02)
The carbenes 16 and 30 were generated in methanol/ sodium methoxide by photolyses of 2-methylchromone tosylhydrazone (14) and 3,5-dimethoxy-4,4-dimethyl-2,5-cyclohexadienone tosylhydrazone (28), respectively.Neither 16 nor 30 accept methanol at the carbenic site to give products of a formal O-H insertion.Carbene 16 affords 2-methoxy-2-methyl-2H-1-benzopyran (19) by way of the benzopyrylium ion 17.The same ether was obtained from the independently prepared perchlorate of 17.Protonation of 30 was followed by demethylation of the delocalized carboxonium ion 31 to give5-methoxy-6,6-dimethyl-2,4-cyclohexadienone (33) as the only product. Key Words: Carbenes, nucleophilic/ Cyclohexadienylidenes/ Pyrylium ions/ Carboxonium ions
HIGH YIELD SYNTHESIS OF FILICINIC ACID, BASED ON THE POLYCHLORINATION OF 4,4-DIMETHYL-2-CYCLOHEXENONE PART II : CONVERSION OF 2,3,5,6-TETRACHLORO-4,4-DIMETHYL-2,5-CYCLOHEXADIENONE INTO FILICINIC ACID AND RELATED CYCLOHEXADIENONES
Buyck, L. De,Kimpe, N. De,Verhe, R.,Schamp, N.
, p. 241 - 248 (2007/10/02)
Filicinic acid (5) was prepared in 75-80percent overall yield from 4,4-dimethyl-2-cyclohexenone (1).The key intermediate, tetrachlorodienone 2, underwent facile substitution of both β-chlorine substituents by methoxide affording the bis enol ether 3 which was converted into dichlorofilicinic acid 4 in hot 85percent sulfuric acid.Monohydroxy derivatives were obtained by treatment of 2 or 3 with hydroxide.Palladium-catalysed low-pressure hydrogenation of 4 under appropiate conditions produced monochlorofilicinic acid, filicinic acid or 5-hydroxy-4,4-dimethyl-1,3-cyclohexanedione (8) with high selectivity.
