- Rearrangement Approaches to Cyclic Skeletons. IV. The Total Synthesis of (+/-)-Pinguisone and (+/-)-Deoxopinguisone Based on Photochemical Acyl Migration of a Bicyclonon-6-en-2-one
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The total synthesis of (+/-)-Pinguisone (2) and (/-)-deoxopinguisone (3), fused ring sesquiterpenes, has been achieved starting from 1-methoxy-3,4,5-trimethylbenzene. 1-Methoxy-4,5,endo-8-trimethylbicyclonon-5-en-2-one (9) was prepared selectively via facial selective Diels-Alder reaction of the diene derived from the benzene and 2-chloroacrylonitrile.Ring enlargement of 9 using (CH3)3SiCHN2 and BF3 etherate gave the corresponding bicyclooct-en-2-one (8).The photochemical acyl migration of 8 gave the fused-ring compound (7).The fourth methyl was introduced selectively by the conjugate addition of (CH3)2CuLi to the spironon-8-ene-3,2'-dioxolan>-7-one prepared from 7.Each furan ring of 2 and 3 was constructed via the corresponding butenolide derived from the γ-keto acid by acid-catalyzed dehydration.
- Uyehara, Tadao,Kabasawa, Yasuhiro,Kato, Tadahiro
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p. 2521 - 2528
(2007/10/02)
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- PHOTOCHEMICAL REARRANGEMENT APPROACH TO THE TOTAL SYNTHESIS OF (+/-)-PINGUISONE AND (+/-)-DEOXOPINGUISONE
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The total synthesis of (+/-)-pinguisone and (+/-)-deoxypinguisone, the unusual fused-ring sesquiterpenes, was accomplished by the photochemical transformation of the bicyclonon-6-en-2-one into the bicyclonon-4-en-7-one.
- Uyehara, Tadao,Kabasawa, Yasuhiro,Kato, Tadahiro
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p. 2343 - 2346
(2007/10/02)
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