Chemo‐ and Regioselective C(sp³)H Arylation of Unactivated Allylarenes by Deprotonative Cross‐Coupling

Abstract

The combination of aryl bromides, allylbenzene, base and a palladium catalyst usually results in a Heck reaction. Herein we combine these same reagents, but override the Heck pathway by employing a strong base. In the presence of LiN(SiMe3)2, allylbenzene derivatives undergo reversible deprotonation. Transmetallation of the resulting allyllithium intermediate to LPdAr(Br) and reductive elimination provide the 1,1-diarylprop-2-enes, which are not accessible via the Heck reaction. The regioselectivity in this deprotonative cross-coupling process is catalyst-controlled and very high.

NiXantphos: A Deprotonatable Ligand for Room-Temperature Palladium-Catalyzed Cross-Couplings of Aryl Chlorides

“…11 In the current study, the scope of Pd–NiXantphos catalyzed DCCP using a variety of aryl chlorides with a model diarylmethane substrate ( 1a ) is presented in Table 4.…”

Palladium-Catalyzed Benzylic C–H Arylation of Azaarylmethylamines

“…Based on our experience in deprotonative cross-coupling reactions 10c–f,11 with weakly acidic substrates, we hypothesized that the reversible deprotonation of (aminomethyl)pyridines in the presence of a palladium catalyst should be possible.…”

Chemoselective palladium-catalyzed deprotonative arylation/[1,2]-Wittig rearrangement of pyridylmethyl ethers

“…In the course of our studies20 in the DCCP of a variety of weakly acidic substrates, we discovered that palladium complexes of van Leeuwen's NIXANTPHOS ligand21 (Table 1) enable a wide variety of transformations whereas other ligands are much less effective. Thus, we employed a Pd(OAc) 2 (5 mol%)/NIXANTPHOS (7.5 mol%) based catalyst to initiate the direct arylation of 2-pyridylmethyl ethyl ether 1a with bromobenzene in combination with 6 bases [LiO– t Bu, NaO– t Bu, KO– t Bu, LiN(SiMe 3 ) 2 , NaN(SiMe 3 ) 2 , and KN(SiMe 3 ) 2 ].…”