Diastereoselective allylation-based asymmetric total synthesis of 1,10- seco -guaianolides.

A Cr(II)-mediated Nozaki-Hiyama allylation of aldehydes with functionalized chiral allylbromolactone paved the way to easily access β-hydroxy-aryl/alkyl-α-methylene-γ-butyrolactones in good yields with high diastereoselectivities. A subsequent undemanding translactonization was orchestrated in the efficient first asymmetric total synthesis of two 1,10- seco -guaianolides as a valuable extension of the strategy developed.