Regio- and Chemoselective Direct Generation of Functionalized Aromatic Aluminum Compounds Using Aluminum Ate Base

A regio- and chemoselective direct method for generation of functionalized aromatic aluminum compounds through deprotonative directed ortho-alumination using triisobutyl(tetramethylpiperidino)aluminate ( i Bu3Al(TMP)Li), prepared by mixing of triisobutylaluminum ( i Bu3Al) and lithium tetramethylpiperidide (LTMP) in THF, has been developed. Deprotonative alumination of various functionalized benzenes with the use of i Bu3Al(TMP)Li proved effective for the direct generation of various ortho-functionalized aluminum aromatic and heteroaromatic derivatives, particularly those with electrophilic functional groups such as cyano, amide, and halogen. Direct alumination, followed by electrophilic trapping (with I2), provided a convenient preparative method for 1,2- or 1,2,3-multisubstituted aromatic compounds. The functionalized aromatic aluminate intermediate also was found to undergo copper- and palladium-catalyzed C−C bond-forming reactions very efficiently and highly regio- and chemoselectively.