A straightforward synthesis of (+/−)-diospongin A starting from benzaldehyde is described. A Prins cyclization reaction to control the relative configuration of the three stereogenic centers and a Mitsunobu inversion represent the key steps of the approach.
The expeditious preparation of allo-sedamine and allo-lobeline via 1,3-diastereoselective aza-Sakurai-Hosomi reaction followed by hydroformylation is reported.