Efficient route to the synthesis of C-2, C-3 substituted 4-piperidones
作者:Dharmpal S. Dodd、Allan C. Oehlschlager
DOI:10.1016/s0040-4039(00)79755-3
日期:1991.7
6-dihydro-4-pyridone ((1) has proven to be exceptionally receptive in the conjugate addition of organocuprates to give C-2substituted piperidones having the C-3 position activated toward alkylation. Enone (1) was used as the key synthon in the synthesis of C-1, C-2 and C-3 substituted 4-piperidinol (8).
Synthesis of inhibitors of 2,3-oxidosqualene-lanosterol cyclase: conjugate addition of organocuprates to N-(carbobenzyloxy)-3-carbomethoxy-5,6-dihydro-4-pyridone.
作者:Dharmpal S. Dodd、Allan C. Oehlschlager
DOI:10.1021/jo00036a008
日期:1992.5
Synthesis of ammonium ion analogues of the first cationic intermediate, 5, presumed to be formed during the cyclization of 2,3-oxidosqualene by 2,3-oxidosqualene-lanosterol cyclase are reported. The required 2,3-substituted-4-piperidinols are prepared by conjugate addition of higher order alkyl (2-thienyl)(cyano)cuprates to 1-(carbobenzyloxy)-3-carbomethoxy-5,6-dihydro-4-pyridone. The nitrogen protecting group (carbobenzyloxy) is key to the synthesis in that it allows the conjugate addition to proceed in high yield and is easily converted to the required N-methyl group in the final products. The key terpenoid side chain appended to C-2 of the piperidinols was constructed from homofarnesyl bromide and 1,5-difunctionalized homoisopentenyl derivatives prepared by zirconium-catalyzed carboalumination of protected 1-butyn-4-ol.