Consecutive Application of the ?-Alkynone Cyclization: Total Synthesis of (�)-?9(12)-Capnellene
作者:Joan Huguet、Martin Karpf、Andr� S. Dreiding
DOI:10.1002/hlca.19820650806
日期:1982.12.15
The synthesis of the (±)-form of the marine sesquiterpene (–)-Δ9(12)-capnellene (1) by double application of the a-alkynone cyclization is described. Starting with 2, 2, 5-trim ethylcyclopentanone (2), the elaboration of the tricyclo [6.3.0.02,6]undecane C-skeleton of 1 proceeded through the a-alkynone 3, which was cyclized thermally to the bicyclo [3.3.0]octenone 4. For the anellation of the third
Electroreduction of gamma and delta-cyano ketones in i-PrOH with Sn cathode gave alpha-hydroxy ketones and their dehydroxylated ketones as the intramolecularly coupled products. Guaiazulene, (-)-valeranone, polyquinanes, dihydrojasmone, methyl dihydrojasmonate, and rosaprostol have been synthesized by utilizing this electroreductive intramolecular coupling of gamma and delta-cyano ketones in one of the key steps. Similarly, electroreduction of a mixture of ketone and nitrile gave the corresponding intermolecularly coupled product. The product obtained by the electroreductive intermolecular coupling of (+)-dihydrocarvone with acetonitrile has been found to be the precursor of an effective chiral ligand for the enantioselective addition of diethylzinc to aldehydes.
Paquette, Leo A.; Stevens, Kenneth E., Canadian Journal of Chemistry, 1984, vol. 62, p. 2415 - 2420