Synthesis of dihydrofurans by metal catalyzed reaction of cyclic diazocarbonyl compound

Abstract

In view of the extensive naMa! occurrence and biological importance of dih\drohenzofuron and luran derivatives it was planned to develop a general and facile method for the synthesis of dihydrofurans through metal mediated eatalYL:ed reactions of qclic diazocarbonyl compounds. An efficient method lor the synthesis of 4-oxo-2, 3.4.5,6. 7-hexahydro-benzofurJn- 2-yl-acetale deri valive, 10-12, 2-chloromethyl- 3,5,6,7- tctrahydro-2H-benzofuran-4-ones 28,29,30 through the rhodium pivalale catalyzed reaction of 2-diazo-cyclohexane-l,3-diones 6-S with vinyl acetate and allyl chloride, respectively in mild condition is reported. Synthesis of 2-phenyl-6, 7_dihydro_51l_benzol\.u'an-4_ones 14,16,18,and 2-ethoxy methyl 3j.6,7-tetrahydro-2H-benzofuran-4-ones 21,23,25 are also developed by rhodium catalyst reaction of 2_diazo-cyelohexane_I,3_diones with phenyl acetylene and allyl ethyl ether respectively under the same reaction condition. In case of phenyl acetylene and allyl ethyl ether spiro compound l_phenyl_spiro(2,5]oct_l_ene_4,8_diones 15,17,18 and 1- elhoxymethyl spiro[2,5]octane-4,8-diones 22,24,26 were obtained respectively as by products. o R,-~+-Jld"-Ac R'IO_12 o RI-0-rCI R, 28.30 o RI~ "- 14. t6,18 o .AAo',/ RI~O -...r R2 22,24,26 Where, All ,the synthesized products were characterized by ~-pectraJ data obtained from IR, UV and lHNMR. All synthesized compounds were tested antibacterial and antifungal activity, some of them demonstrated mild to moderate antimicrobial activity against most of the test organism.