HIGH SELECTIVITY INDUCED BY NEIGHBORING-GROUP EFFECTS IN C-C BOND-FORMING REACTIONS WITH ORGANOTRANSITION-METAL REAGENTS

Basic groups (e.g. OH, OMe, NMe(2)) in the neighbourhood of electrophi lic functional groups of organic molecules are recognized by nucleophi lic organotransition reagents [e.g. MeCrCl(2)(THF)(3), Bu(2)Mn, (allyl )(2) VCl,NCCH2FeCl, EtO(2)CCH(2)CoCl, [vinylTi (OiPr)(4)]Li] and accel erate or inhibit C-C bond-forming reactions at the electrophilic funct ion. These neighbouring-group effects enable highly selective (chele- and anticheleselectivity, stereoselectivity) reactions on ketones, ald ehydes, epoxides and vinyl bromides.