Reported is a versatile new oxidative method for the arylation of activated methylene species. Under mild reaction conditions (RT to 40 °C), Cu(OTf)2 mediates the selective coupling of functionalized aryl boron species with a variety of stabilized sp(3) -nucleophiles. Tertiary malonates and amido esters can be employed as substrates to generate quaternary centers. Complementing either traditional cross-coupling or SN Ar protocols, the transformation is chemoselective in the presence of halogen electrophiles, including aryl bromides and iodides. Substrates bearing amide, sulfonyl, and phosphonyl groups, which are not amenable to coupling under mild Hurtley-type conditions, are suitable reaction partners.

Reported is aversatile new oxidative method for the arylation of activated methylene species.U nder mild reaction conditions (RTt o4 0 8 8C), Cu(OTf) 2 mediates the selective coupling of functionalized aryl boron species with avariety of stabilized sp 3 -nucleophiles.T ertiary malonates and amido esters can be employed as substrates to generate quaternary centers.C omplementing either traditional cross-coupling or S N Ar protocols,t he transformation is chemoselective in the presence of halogen electrophiles,including aryl bromides and iodides.S ubstrates bearing amide,s ulfonyl, and phosphonyl groups,w hicha re not amenable to coupling under mild Hurtley-type conditions,are suitable reaction partners.Cross-coupling reactions between two distinct nucleophilic partners have emerged as valuable transformations which display reactivity and selectivity orthogonal to classical metalcatalyzed couplings of electrophiles with nucleophiles. [1] Oxidative coupling reactions often proceed under exceptionally mild reaction conditions,employ base-metal mediators or catalysts,a nd in ideal cases,t olerate electrophilic functionality useful for subsequent transformations.T he coppermediated union of aryl boronic acids and heteroatom nucleophiles exemplifies the power of such coupling manifolds. [2] First reported by Chan, Lam and co-workers, [3] and Evans et al., [4] functionalized aniline and phenol derivatives can be prepared from stable,r eadily available aryl boron species at room temperature by employing simple copper salts and mild organic bases.I na ddition to N-and O-based nucleophiles,s ulfur,s elenium, tellurium, and halogen nucleophiles are also suitable partners in these reactions. [2,5,6] Despite the success of Chan-Evans-Lam-type reactions in carbon-heteroatom bond construction processes,aswell as an increasing appreciation for the mechanism of these transformations, [7] ageneral method for the copper-mediated arylation of stabilized sp 3 -carbon-based nucleophiles with organoboron reagents has not been established. This is particularly noteworthy in light of the importance of a-aryl carbonyl compounds in synthetic organic and medicinal chemistry,and the considerable body of literature concerning transition-metal-based methods for their synthesis by the coupling of sp 2 electrophiles. [8][9][10] Indeed, in comparison to heteroatom nucleophiles,r eports of copper promoting CÀC bond-forming reactions with aryl boron reagents under oxidative conditions remain sparse. [11,12] To the best of our knowledge,enamine annulation [13] and vinylation [14] represent the closest known reports towards an enolate Chan-Evans-Lam reaction. Currently available oxidative arylation strategies employing organoboron reagents and activated methylenes require stoichiometric amounts of Pb(OAc) 4 in combination with mercury additives. [15] Motivated by this methodological gap and the opportunity to access compound classes not easily prepared by existing protocols,w er eport herein the first copper-mediated oxidative coupling reactions betw...

In this new oxidative method for the arylation of activated methylene species Cu(O‐Tf)2 mediates the selective coupling of functionalized aryl boron species with stabilized sp3‐nucleophiles.

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