Total Synthesis and Biological Activity of (±)‐Rocaglamide and Its 2,3‐Di‐epi Analogue

By introducing the strategy of intramolecular reductive coupling to construct the cyclopenta[ b ]benzofuran skeleton, the shortest and most efficient synthetic method hitherto was now established to rocaglamide 1 and its 2,3‐di‐ epi analogue 3 in racemic form by Michael addition, SmI 2 ‐promoted intramolecular keto–ester coupling, amination of the ester intermediate, and reduction of carbonyl with Me 4 NBH(OAc) 3 . Several steps were highly stereoselective or even stereospecific. The bioassay results indicated that both 1 and 3 were much better repellents against Plutella xylostella than azadirachtin; the insecticidal activity of 1 was higher than that of azadirachtin against Pieris rapae , P. xylostella , Laphygma exigua , and Helicoverpa armigera , but that of 3 was lower.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008)