Beilstein J. Org. Chem.2008,4, No. 31, doi:10.3762/bjoc.4.31
synthesis of compound 22 began with double alkylation of (+)-21 through a cuprate conjugate addition followed by treatment of the resulting enolate with methyl iodide (Scheme 5). Retro-Diels-Alder reaction of 22 in refluxing 1,2-dichlorobenzene gave α,β-unsaturatedketone 23. Trisubstituted cyclopentanone
NaBH4) of the nitrile, MOM protection of the newly formed primary alcohol, and hydrolysis of the dioxolane gave ketone 30 and occurred as a prelude to retro-Diels-Alder reaction of the latter, leading to the α,β-unsaturatedketone 31. Compound 32 was obtained by treatment with LDA and Mander’s reagent
Beilstein J. Org. Chem.2005,1, No. 2, doi:10.1186/1860-5397-1-2
from oxidation to the corresponding α,β-unsaturatedketone,[47] followed by conjugate addition.
The dihydroxyation of the anti allylic alcohol 19 under Upjohn conditions was not synthetically useful (entry 8a, Table 1). Although dihydroxyation of the remote allyl group was rapid, the dihydroxylation of