Borylation of organo halides and triflates using tetrakis(dimethylamino)diboron

Advances in Base-Metal Catalysis: Development of a Screening Platform for Nickel-Catalyzed Borylations of Aryl (Pseudo)halides with B2(OH)4

“…During our studies of nickel-catalyzed borylations of various aryl halides relevant to current projects within our department, we discovered that improved yields can be obtained for difficult substrates by the addition of 2.0 equiv of a diol (generally 1,3-propanediol or neopentyl glycol) relative to B 2 (OH) 4 . Reports in the literature suggest that the addition of a diol to the borylation reaction mixture can convert tetrahydroxydiboron (or its synthetic precursor tetrakis­(dimethylamino)­diboron) to the corresponding bis­(diolato)­diboron species. , This species is capable of undergoing palladium-catalyzed borylation to afford the corresponding boronate ester, which can be isolated as the organotrifluoroborate or cross-coupled with an aryl halide in a one-pot reaction. In order to probe the effect of the diol in the case of nickel-catalyzed borylations, we performed a series of stability experiments with B 2 (OH) 4 (Figure ).…”

Diboron(4) Compounds: From Structural Curiosity to Synthetic Workhorse

“…The Molander group also demonstrated the use of tetrakis­(dimethylamino)­diboron (B 2 (NMe 2 ) 4 ) as the borylating agent for aryl chlorides and bromides . Additionally, B 2 (NMe 2 ) 4 was also used as the starting diboron(4) compound in the borylation of aryl bromides by an in situ generated B 2 (diol) 2 (Scheme a) . Complete conversion to the B 2 (diol) 2 from B 2 (NMe 2 ) 4 and 2 equiv of diol was observed in solution, and the reactivity of the borylated products in a subsequent (one-pot) Suzuki–Miyaura reaction differed, based on the nature of the diol used.…”

A modified procedure for the palladium catalyzed borylation/Suzuki-Miyaura cross-coupling of aryl and heteroaryl halides utilizing bis-boronic acid

“…12 This work reported an improvement in yields in the presence of bulkier diols, which they attribute to the Thorpe-Ingold effect. The authors hypothesize that a boronate ester is formed by addition of the diol.…”