Synthesis of (2S,3R,4S)-Isonorstatine Using a Solvent-Induced Highly Stereoselective 3-Butenyl Addition to l-Threose Imines

Abstract Isonorstatine was obtained in an 11-step sequence starting from L-tartaric acid, based on a highly stereoselective addition of 1-butene-3-yl to a threose imine. The orientation of the methyl group at C-4 of isonorstatine was determined by transformation of the key δ-XYLO adduct into a δ-lactone. This also shows that both termini of the key adduct, the diol acetonide and vinyl moiety, can be elaborated selectively into an acid function leading to both aminohydroxymethyl acid and diacid derivatives.