Efficient Total Synthesis of (±)-Isoguaiacin and (±)-Isogalbulin

Abstract

1-Arylnaphthalene lignans such as (–)-isoguaiacin and (–)-isogalbulin have been reported to exhibit notable biological properties. While (–)-isoguaiacin has not been previously synthesized, syntheses of (–)-isogalbulin are generally long and produce a mixture of stereoisomers. We herein present the efficient total synthesis of (±)-isoguaiacin and (±)-isogalbulin in seven and eight steps with an overall yield of 46% and 36%, respectively. The reported approach harnesses a hydrogenolysis reaction in acidic conditions, to convert a furan into an arylnaphthalen structure.

Total Syntheses and Absolute Stereochemical Correction of Negundin B, Vitexin 1, and Vitexin 6

“…With the synthesis of vitexin 1 completed it was decided to prepare the related vitexin 6 due to its prevalence in biological studies, ,,, but again reported without analysis of its absolute configuration. Vitexin 6 is the dimethyl ether of vitexin 1, and therefore selective methylation of the more reactive phenols in vitexin 1 was attempted; however, despite numerous attempts vitexin 1 did not react and the reaction only returned starting material. It was therefore decided that vitexin 6 would be synthesized using the developed synthetic route (see compounds 4 to 12c in Scheme ) using veratraldehyde as the aldehyde in both aldol steps.…”