A New Reaction Sequence Involving Palladium‐Catalyzed Unsymmetrical Aryl Coupling.

Abstract

For Abstract see ChemInform Abstract in Full Text.

Modular and regioselective synthesis of all-carbon tetrasubstituted olefins enabled by an alkenyl Catellani reaction

“…Besides intermolecular couplings, an intramolecular ortho alkylation/redox-Heck annulation was achieved 43,44 , which provides a rapid synthesis of tricycles containing an all-carbon tetrasubstituted olefin and an adjacent quaternary stereocenter (7d and 7e). Furthermore, beyond alkylation at the vicinal C2 position, this catalytic system was also effective for C2-arylation using aryl bromides 21,22 as the external electrophile (9a-9c).…”

“…Taking advantage of a unique aryl-norbornyl-palladacycle (ANP) intermediate, an electrophile could be introduced at the ortho position, while a nucleophile could be coupled at the ipso position, thus allowing vicinal difunctionalization of aryl halides ( Fig. 2a) 13,[20][21][22] . One would imagine that, the corresponding reaction with alkenyl halides as substrates would afford distinct access to all-carbon tetrasubstituted olefins in a regioselective manner.…”

Catellani Reaction: An Enabling Technology for Vicinal Functionalization of Aryl Halides by Palladium(0)/Norbornene Cooperative Catalysis

“…In 2004, the Catellani group reported that biphenyls, with two different substituents, were selectively formed by the Pd‐catalyzed unsymmetrical aryl coupling reaction of aryl iodides with aryl bromides and terminal olefins. [ 63 ] Interestingly, if a less reactive o ‐bromobenzoate was used as the reactant, a single product 51 could be selectively obtained (Scheme 24a). In the process of exploring the scope of substrates, Catellani found that attaching electron‐withdrawing or ortho ‐chelating groups to aryl bromides could increase their reactivity to ANP, while changing the electron‐donating group or non‐chelating ortho ‐substituent attached to the aryl iodide was more suitable.…”

Trifunctionalization of Aryl Iodides with Two Distinct Nitrogen and Carbon Electrophiles by Palladium/Norbornene Catalysis

“…[ 6‐8 ] Among them, the palladium/norbornene (Pd/NBE) catalysis, which was first discovered by Catellani et al ., [ 9 ] has emerged as a powerful approach for the assembly of 1,2,3‐trisubstituted arenes via vicinal difunctionalization of aryl halides (Scheme 1). [ 10‐23 ] Typically, an electrophile ( E ) and a nucleophile ( Nu ) are regioselectively installed at the ortho and ipso positions of mono‐ortho ‐substituted aryl halides, [ 24‐32 ] by taking advantage of the unique reactivity of aryl‐NBE palladacycle ( C 6 ‐ANP ). In particular, if ortho ‐unsubstituted aryl halides are used, the further C―H functionalization [ 33 ] would generally take place to form a second palladacycle ( C 2 ‐ANP ), thus affording symmetrical trisubstituted arenes via difunctionalization at three adjacent sites.…”