Diastereo- and enantioselective intramolecular 1,6-C–H insertion reactions of α-diazo esters catalyzed by chiral dirhodium(II) carboxylates

Abstract The first catalytic asymmetric intramolecular 1,6-C–H insertion reaction of α-diazo esters is described. With dirhodium(II) tetrakis[ N -phthaloyl-( S )- tert -leucinate], Rh 2 ( S -PTTL) 4 , the C–H insertion proceeded in a chemoselective manner to give 2-alkenyltetrahydropyran-3-carboxylates with up to 95% ee and perfect cis diastereoselectivity.