Total Synthesis of (+)-Galbulin and Unnatural Lignans
作者:Florian Clausen、Armido Studer
DOI:10.1021/acs.orglett.0c02294
日期:2020.9.4
The total synthesis of (+)-galbulin was achieved in 15% yield and 99% ee over eight steps from commercially available 4-veratraldehyde. The key steps include Meyer’s asymmetric tandem addition to a chiral 2-oxazoline-substituted naphthalene, a Pd-catalyzed stereospecific decarboxylative γ-arylation, and a formal anti-Markovnikov hydromethylation. In addition, five unnatural lignans were synthesized
Birch reductio and reductivemethylations of some substituted naphtholic acids have been examined. The factors influencing the mechanism of reduction process have been discussed. Some of the reduced naphthoic acids are useful synthons for synthesis.