A scalemic synthesis of the scopadulcic acid skeleton. I: An efficient γ-alkylation at C-9 in abietane framework and subsequent aldol reaction
作者:Jayaram R. Tagat、Stuart W. McCombie、Mohindar S. Puar
DOI:10.1016/0040-4039(96)01947-8
日期:1996.11
The first example of a carbon-carbon bond formation at C-9 in the abietaneframework via a highly practical γ-alkylation of the enone 6 is reported. Attempted intra-molecular aldolreaction of the derived enone aldehyde 13 gave exclusively the undesired product 14. However, the 12-methyl enone aldehyde 17 gave a trace of the desired aldol 19, bond formation at C-7 still being the major pathway.
A scalemic synthesis of the scopadulcic acid skeleton. II: Ring-D formation via regiospecific intramolecular aldol and alkylation reactions
作者:Jayaram R. Tagat、Mohindar S. Puar、Stuart W. McCombie
DOI:10.1016/0040-4039(96)01948-x
日期:1996.11
The propensity of abietenones such as 2 to form exclusively the extended enol(ate) into ring-B can be curbed by introducing an alkoxy group at C-7 in the abietane framework. Thus, the 7- trimethylsilyloxy enone-aldehydes 11 and 13 cyclize to form the C-12 aldol products 12 and 14. Furthermore, the 9-iodoethyl-12-methyl-enone 19 cyclizes via its putative enol to give the tetracyclic enone 20. Compounds