SYNTHESIS OF OPTICALLY-ACTIVE FERROCENE ANALOGS OF SALICYLIC-ACID DERIVATIVES AND RHODIUM(II)-CATALYZED ASYMMETRIC INTRAMOLECULAR-C-H INSERTION OF ALPHA-DIAZO BETA-KETO-ESTERS USING NEW CHIRAL CARBOXYLATO LIGANDS

The ferrocene analogue of salicylic acid, 2-hydroxyferrocenecarboxylic acid was synthesized via monolithiation of ferrocene with t-butyllith ium, and resolved to optically active forms. Optically active 2-hydrox yferrocene-carboxylic acid was converted to 1-hydroxyferrocenecarbalde hyde, ferrocene analogue of salicylaldehyde, and 2-alkoxyferrocenecarb oxylic acids. The later compounds were used as chiral carboxylato liga nds for the rhodium(II)-catalyzed asymmetric intramolecular C-H insert ion of alpha-diazo beta-keto esters (up to 42% ee).