Synthesis of 2, 3, 4, 6, 7, 8??Hexahydro??5H??1??benzopyran??5??ones and 3??(6??Oxo??1??cyclohexenyl) alkanoic Acids by Reduction of 4, 6, 7, 8??Tetrahydro??2H??1?? …
H Hombrecher, P Margaretha, P Tissot
文献索引：Hombrecher, Hermann; Margaretha, Paul; Tissot, Paul Helvetica Chimica Acta, 1986 , vol. 69, p. 1681 - 1684
Abstract Comparative results on the reduction of 4, 6, 7, 8-tetrahydro-7, 7-dimethyl-2H-1- benzopyran-2, 5 (3H)-diones 1 are reported. Hydride reduction (LiAlH 4 in Et 2 O or NaBH 4 in i-PrOH) affords 2, 3, 4, 6, 7, 8-hexahydro-5H-1-benzopyran-5-ones 5 in 30-60% isolated yield. Photochemical reduction of 1b and 1d (direct irradiation at λ= 300 or 254 nm in i-PrOH, or sensitized irradiation in acetone/i-PrOH or benzene/i-PrOH) gives 3-(6-oxo-1- ...
