Gold-catalyzed naphthalene functionalization

Abstract

SummaryThe complexes IPrMCl (IPr = 1,3-bis(diisopropylphenyl)imidazol-2-ylidene, M = Cu, 1a; M = Au, 1b), in the presence of one equiv of NaBAr'4 (Ar' = 3,5-bis(trifluoromethyl)phenyl), catalyze the transfer of carbene groups: C(R)CO2Et (R = H, Me) from N2C(R)CO2Et to afford products that depend on the nature of the metal center. The copper-based catalyst yields exclusively a cycloheptatriene derivative from the Buchner reaction, whereas the gold analog affords a mixture of products derived either from the formal insertion of the carbene unit into the aromatic C–H bond or from its addition to a double bond. In addition, no byproducts derived from carbene coupling were observed.

Iron and Manganese Catalysts for the Selective Functionalization of Arene C(sp2)−H Bonds by Carbene Insertion

“…Di- (Figure 1f)a nd tri-substituted benzenes (Figure 1g,h) verified the same behavior. [19] The related tetrahydronaphtalene was also modified in the aromatic ring in an exclusive manner. [18] Naphthalene also displayed functionalization toward the insertion product, albeit this substrate has shown at endency to provide cyclopropanation derivatives.…”

“…[19] The related tetrahydronaphtalene was also modified in the aromatic ring in an exclusive manner. These values can be associated with the involvement of electrophilic metallocarbene intermediates.In the aforementioned work from Wooand co-workers, [19] values within the range À1.11 to À0.82 were found for the iron-based catalysts.A dditionally,k inetic isotopic experiments [Eq. It is worth pointing out that the acidcatalyzed conversion of the insertion into addition products described by McKervey and co-workers [20] has been discarded on the basis of control experiments (see the Supporting Information).…”

“…[18] Naphthalene also displayed functionalization toward the insertion product, albeit this substrate has shown at endency to provide cyclopropanation derivatives. [19] The related tetrahydronaphtalene was also modified in the aromatic ring in an exclusive manner. Finally,t he substrates containing electron-withdrawing groups (Cl, CF 3 )d isfavored this transformation.…”

“…As inferred from entries 4-9, in experiments carried out with (L 1 )FeX 2 pre-catalysts,the amount of NaBAr 4 F influenced the yield (a control experiment with NaBAr 4 F as the sole additive did not induce any reaction) that moved from 65 to 86 %( EDA-based, see the Supporting Information). On the other hand, the addition of just one equiv of NaBAr F 4 did not induce the reaction, most of the EDAr emained unreacted after several hours.B ut the most remarkable aspect observed is the unprecedented observation of complete selectivity toward the insertion product as the sole derivative formed from benzene with the series of Fe or Mn tridentate or tetradentate ligand-containing catalyst precursor (entries 4- 19). In all cases,t he products derived from the formal carbene CHCO 2 Et homocoupling,d iethyl fumarate and maleate,w ere not formed in detectable amounts.I na ddition, virtually identical product yields and selectivities were obtained by using (L 1 )FeCl 2 and (L 1 )Fe-(OTf) 2 precatalysts strongly suggesting that identical active species are generated in both cases.Use of the Mn precatalyst (L 1 )Mn(OTf) 2 (entry 10) also produced the selective formation of the insertion product, but with as lightly lower yield.…”

Catalytic functionalization of low reactive C(sp3)–H and C(sp2)–H bonds of alkanes and arenes by carbene transfer from diazo compounds

“…48 Other substrates such as naphthalene have also been modified with this strategy. 49 At this stage, it is worth noting the work carried out by McKervey and co-workers showing the arrangement of cycloheptatrienes into the insertion products in the presence of acid. 50 61 In all cases, a net incorporation of the carbene group at the ortho position is observed, albeit in some cases a subsequent transformation involving the directing group takes place, providing molecular complexity beyond the mere C-H functionalization.…”