Thermal Conversion of Methyl 8-Vinyl-3-oxo-2-oxabicyclo[2.2.2]oct-5-en-6-carboxylates to Tetrahydrocoumarins and Methyl Benzoates
摘要:
Methyl 8-methyl- and 8-methoxy-8-vinyl-3-oxo-2-oxabicyclo[2.2.2]oct-5-en-6-carboxylates (3 and 5), prepared by the Diels-Alder reaction of methyl 2-oxo-2H-pyran-5-carboxylate with 2-methyl- and 2-methoxy-1,3-butadienes, were converted into methyl 9-methyl- and 9-methoxy-3-oxo-2-oxabicyclo[4.4.0]deca-4,8-diene-6-carboxylates (tetrahydrocoumarins) by a Cope rearrangement at about 140-degrees-C, respectively. On the other hand, 3 and 5 were transformed into methyl 4-isopropyl- and 4-acetylbenzoates via the reaction of methyl tricyclo[3.2.1.0(2,7)]oct-3-en-4-carboxylates at about 257-degrees-C in the presence of Pd-C, respectively.
Thermal Conversion of Methyl 8-Vinyl-3-oxo-2-oxabicyclo[2.2.2]oct-5-en-6-carboxylates to Tetrahydrocoumarins and Methyl Benzoates
摘要:
Methyl 8-methyl- and 8-methoxy-8-vinyl-3-oxo-2-oxabicyclo[2.2.2]oct-5-en-6-carboxylates (3 and 5), prepared by the Diels-Alder reaction of methyl 2-oxo-2H-pyran-5-carboxylate with 2-methyl- and 2-methoxy-1,3-butadienes, were converted into methyl 9-methyl- and 9-methoxy-3-oxo-2-oxabicyclo[4.4.0]deca-4,8-diene-6-carboxylates (tetrahydrocoumarins) by a Cope rearrangement at about 140-degrees-C, respectively. On the other hand, 3 and 5 were transformed into methyl 4-isopropyl- and 4-acetylbenzoates via the reaction of methyl tricyclo[3.2.1.0(2,7)]oct-3-en-4-carboxylates at about 257-degrees-C in the presence of Pd-C, respectively.