Stereochemically controlled cyclopropanation of (S)-glyceraldehyde acetonide-derived olefins.: Synthesis of (2S,1′R,2′R,3′R)-2-(2′,3′-dicarboxycyclopropyl)glycine

[GRAPHICS] The reactions of ethyl (dimethylsulfuranylidene)acetate or other related sulfonium ylides with olefins 1 derived from (S)-glyceraldehyde acetonide provide cyclopropanation products in good to excellent diastereoselectivity. On the basis of this reaction, a new synthetic protocol for (2S,1'R,2'R,3'R)-2-(2',3'-dicarboxycyclopropyl)glycine (L-DCG-IV), an isotype-selective agonist of metabotropic glutamate receptors, is developed.