Efficient RhII binaphthol phosphate catalysts for enantioselective intramolecular tandem carbonyl ylide formation-cycloaddition of α-diazo-β-keto esters
Catalytic enantioselective tandem carbonyl ylide formation-cycloadditions of alpha-diazo-beta-keto ester 1 using 0.5 mol% dirhodium tetrakis(1,1'-binaphthyl-2,2'-diyl phosphate) catalysts 7-9 and 14 to give the cycloadduct 3 in good yields and up to 90% ee are described.