CgPhen-DalPhos Enables the Nickel-Catalyzed O-Arylation of Tertiary Alcohols with (Hetero)Aryl Electrophiles

Abstract

While the Ni-catalyzed cross-coupling of primary or secondary aliphatic alcohols and (hetero)aryl electrophiles is known, related crosscouplings involving tertiary aliphatic alcohols, with a broad scope, are challenging. Herein we disclose that a Ni II precatalyst featuring the ligand CgPhen-DalPhos is unusual in its ability to promote the C−O cross-coupling of tertiary aliphatic alcohols with (hetero)aryl halides (Cl, Br, and I) or phenol derivatives (OMs and OPiv). An exploration of substrate scope and competition experiments help to shed light on the capabilities and reactivity preferences of this catalyst system.

Acetate Facilitated Nickel Catalyzed Coupling of Aryl Chlorides and Alkyl Thiols

“…Therefore, our goal was to develop a general method for the nickel-catalyzed coupling of aryl chlorides with primary, secondary, and especially tertiary aliphatic thiols. We achieved this by employing the precatalyst (Xantphos)­Ni­( o -tolyl)Cl ( C1 ; Xantphos = (9,9-dimethyl-9 H -xanthene-4,5-diyl)­bis­(diphenyl-phosphane)), first reported by Jamison et al as an air-stable, easily synthesized Ni­(II) precursor, together with potassium acetate as a low-cost and air-stable base at room temperature (Scheme b). We present the results of our investigation on the substrate scope together with mechanistic studies, which uncovered the plausible role of acetate in the catalytic cycle.…”

A C-to-O atom-swapping reaction sequence enabled by Ni-catalyzed decarbonylation of lactones

“…Oxidative addition into the relatively inert C(acyl)–O bond of an ester 8,9 generally requires an electron-rich ligand on the metal complex. 10 The ligand also has to promote a challenging Csp 2 –O reductive elimination from a Ni( ii )(aryl)(aryloxo) complex, 11–14 which is faster from a more electron-deficient metal center bearing bulky ligands. 15 Dcype, a bisphosphine ligand used in Yamaguchi's decarbonylation reaction and a widely employed ligand for decarbonylative transformations, 9 c ,16 did not give any yield of 2a from 1a.…”

Recent Advances in Non-Precious Metal Catalysis

“…These strategies provide quick access to an array of alkyl, vinyl, and aryl halides of relevant structures to pharmaceutically interesting compounds. Other notable advances in Ni-catalyzed reactions include publications entitled (1) CgPhen-DalPhos enables the nickel-catalyzed O-arylation of tertiary alcohols with (hetero)­aryl electrophiles, (2) Synthesis of multisubstituted allenes via nickel-catalyzed cross-electrophile coupling, and (3) Nickel-catalyzed ring-opening allylation of cyclopropanols via homoenolate …”