inexpensive and atom‐economical approach to CH bond functionalization, a cationic CoIII complex (see scheme) was used to generate nucleophilic organometallic species in situ without additional activating reagents. Under these conditions, aryl CH bonds underwent efficient addition to polar electrophiles, including α,β‐unsaturated N‐acyl pyrroles as β‐substituted ester and amide surrogates.
Overriding innate reactivity: The utility of a CoIII catalyst to promote the C2‐selective addition of indoles to imines was demonstrated. The CoIII catalyst completely changed the regioselectivity in comparison with simple Lewis acid catalyzed Friedel–Crafts C3‐selective addition. High turnover number (TON) of the catalyst, up to 1.8×102 (with s/c=200; see scheme; s/c is the substrate/catalyst ratio)
超越先天的反应性:证明了Co III催化剂可促进吲哚向亚胺的C2选择性加成。与简单的路易斯酸催化的Friedel–Crafts C3选择性加成相比,Co III催化剂完全改变了区域选择性。获得了高达1.8×10 2的高周转率(TON)(s / c = 200;参见方案; s / c是底物/催化剂的比例)。
Catalytic Asymmetric Vinylogous Mannich Reaction of <i>N</i>-(2-Thienyl)sulfonylimines
作者:Alvaro Salvador González、Ramón Gómez Arrayás、Marta Rodríguez Rivero、Juan C. Carretero
DOI:10.1021/ol8019082
日期:2008.10.2
Both cyclic and acyclic silyl dienol ethers participate efficiently in the asymmetricvinylogousMannichreaction of N-2-thienylsulfonylimines catalyzed by copper(I) complexes of Fesulphos ligands. This procedure displays wide imine and nucleophile versatility, high enantiocontrol, and complete gamma-regioselectivity in most cases examined. The mild sulfonamide deprotection allows the resulting products