Cascade reactions spiroacetal synthesis

J. Barluenga, A. Mendoza, E Rodriguez, F. J. Fanands, Angew. Chem. Int. Ed. 2009, 48, 1644-1647. A palladium(II)-cata-lyzed synthesis of spiroacetals through a one-pot multicomponent cascade reaction. 

Following their initial studies on the real structure of ( )-berkelic acid previously mentioned, Fiirstner and coworkers published in 2010 a total synthesis of this natural product. The successful route was based on an aldol reaction between methyl ketone 13 and benzaldehyde derivative 14 to give enone derivative 12 (Scheme 3). A subsequent deprotection/1,4-addition/ spiroacetalization cascade reaction delivered the tetracyclic core 11. Installation of the lateral chain was achieved by oxidative rupture, reduction, and... 

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