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The palladium-catalyzed cross-coupling reaction of trialkylbismuth reagents with aryl and heteroaryl halides and triflates is reported. Moderate to good yields were obtained for the transfer of primary alkyl groups. The reaction tolerates numerous functional groups on the electrophilic and nucleophilic partners. The crosscoupling of a-bromostyrene with tris(1,3-dioxan-2-ylethyl)bismuth is also reported.The introduction of alkyl groups onto aryl and heteroaryl scaffolds is highly valuable in medicinal chemistry since it facilitates the search for new interactions between a bioactive compound and its receptor and the exploration of new binding pockets. 2 The transfer of alkyl groups via cross-coupling reactions between alkyl-metal species and aryl or heteroaryl halides and pseudo halides has emerged as a powerful approach for the preparation of such compounds. 3 However, the coupling of alkyl groups possessing hydrogen atoms in the b-position represents a significant challenge due to a slower reductive elimination 4 and the propensity of such groups to undergo b-hydride elimination. 5 To overcome these issues, novel ligands, catalysts, and additives have been developed for the coupling of alkylboron, 6 alkylzinc, 7 and alkylmagnesium 8 species. These advances have also found applications in the transfer of alkyl chains using organoaluminum, organogallium, and organoindium reagents. 9 Nevertheless, some of these methods suffer from poor functional-group tolerance or require excess organometallic species, strictly anhydrous conditions, or complex catalytic systems. Consequently, the development of simple and general procedures for the coupling of sp 3 groups is still highly desirable.Organobismuth reagents have found applications in C-C, C-O, and C-N bond-forming reactions, in part due to their unique reactivity, the low toxicity, and low costs associated with bismuth salts. 10 While the cross-coupling of triarylbismuth reagents is well documented, 11 to our knowledge, the coupling of trialkylbismuth species is unprecedented. 12 As part of our research program dedicated to studying the reactivity of organobismuth reagents, 13 we were interested in developing conditions for the transfer of alkyl groups onto highly functionalized scaffolds through cross-coupling reactions involving trialkylbismuthanes. In order to have high synthetic value, we aimed for a method that used commercially available ligands and catalysts, demonstrated excellent functional-group tolerance, and did not require isolation of the trialkylbismuth reagent.We recently reported the synthesis of tricyclopropylbismuth and its use in palladium-catalyzed cross-coupling reactions with aryl and heteroaryl halides and triflates. 14 As an extension to this methodology, the coupling of triethylbismuth with ethyl 4-bromobenzoate was shown to provide the cross-coupling product in good yield, demonstrating that the protocol is applicable to the transfer of primary sp 3 groups that are susceptible to b-hydride elimination. Encouraged by this result, we initiated...

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Enantioselectivity in heterogeneous catalysis can be induced through the adsorption of optically active compounds known as chiral modifiers. The modifiers typically stereodirect prochiral reactants on the metal surface through the formation of diastereomeric complexes. Surface science measurements on model systems show several examples where such complexes display multiple abundant binding configurations. Insights into the factors determining the relative populations of complexation states can be potentially gained from comparing slightly variant chiral modifiers. Here, we compare scanning tunneling microscopy (STM) data for chirality transfer complexes formed by (R)-1-(1-naphthyl)­ethylamine and (R)-1-(8-methyl-1-naphthyl)­ethylamine coadsorbed with the prochiral substrate 2,2,2-trifluoroacetophenone in order to probe for changes induced by the methyl substituent. The comparison shows changes in relative abundances beyond those predicted by only direct steric interaction. Density functional theory (DFT) methods are used to calculate complexation energies. A number of rationalizations are proposed for the experimentally determined differences in relative abundances and also for differences between DFT-predicted and STM-measured populations.