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Mechanistic investigations of a Rh(I)-catalyzed direct C-H alkylation of benzylic amines with alkenes, formally an C(sp 3 )-H activation, reveal this reaction to proceed via imine intermediates and, hence, via C(sp 2 )-H activation. The reaction shows a primary kinetic isotope effect of 4.3 at the benzylic C-H position together with a reversible H-D exchange at the same position, which indicates that there are at least two distinct steps in which the corresponding C-H bonds are broken. The imine intermediates are shown to be converted to the final product under the reaction conditions, and a time course analysis of the alkylated imine intermediate shows that it is formed before the final amine product in the course of the reaction.

Substituted azafluorenones were synthesized from different dihalogeno diaryl ketones under palladium catalysis by combining either Suzuki or Heck coupling with direct cyclizing arylation. Conditions were identified to allow both auto-tandem processes to proceed successfully from 3-(bromobenzoyl)- or 3-benzoyl-4-bromo-2-chloropyridines, as well as 4-benzoyl-2,3- and 4-benzoyl-2,5-dichloropyridines.

A series of chloro- and bromopyridines have been deprotometalated by using a range of 2,2,6,6-tetramethylpiperidino-based mixed lithium-metal combinations. Whereas lithium-zinc and lithium-cadmium bases afforded different mono- and diiodides after subsequent interception with iodine, complete regioselectivities were observed with the corresponding lithium-copper combination, as demonstrated by subsequent trapping with benzoyl chlorides. The obtained selectivities have been discussed in light of the CH acidities of the substrates, determined both in the gas phase and as a solution in THF by using the DFT B3LYP method., (Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

Deprotonative cupration of aromatic compounds by using amino-based lithium cuprates was optimized with 2,4-dimethoxypyrimidine and 2-methoxypyridine as the substrates and benzoyl chloride as the electrophile. [(tmp)(2)CuLi] (+2 LiCl) (tmp=2,2,6,6-tetramethylpiperidino) was identified as the best reagent and its use was extended to anisole, 1,4-dimethoxybenzene, other substituted pyridines, furan, thiophene and derivatives, and N-Boc-indole (Boc=tert-butyloxycarbonyl). Of the electrophiles employed to attempt the interception of the generated aryl cuprates, aroyl chlorides, iodomethane, and diphenyl disulfide efficiently reacted. In addition, different oxidative agents were identified to afford symmetrical biaryls. Finally, palladium-catalyzed coupling with aryl halides was optimized and allowed the synthesis of different aryl derivatives in medium to good yields., (Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)