Reactivities of mixed organozinc and mixed organocopper reagents: 9. Solvent dependence of group transfer selectivity in sp3C coupling and acylation of mixed diorganocuprates and diorganozincs

Reactivity of mixed organozinc and mixed organocopper reagents: 11. Nickel‐catalyzed atom‐economic aryl–allyl coupling of mixed (n‐alkyl)(aryl)zincs

“…As transition metal catalysts, the mostly used Cu, Ni and Pd catalysts for organozinc reagents were studied. Donor solvents were used as co‐solvents and some Lewis base and Lewis acid reagents were also tested as additives …”

“…HMPA, being the solvent of choice, gave total coupling with a yield of 95% and n ‐Bu transfer:Ph transfer ratio of 82:18. As observed in the reaction of 1ab with allyl bromide, N , N , N ′, N ′‐tetramethylethylenediamine (TMEDA) decreased both the total coupling yield and n ‐Bu transfer (entry 7). 2,2′‐Bipyridyl and urotropine were also tested (entries 8 and 9) as Lewis bases in optimized equimolar amounts to allylic substrate 2 .…”

“…However, Erdik and co‐workers in their serial work on the reactivity and group selectivity of mixed organometallics reported that the group selectivity of mixed diorganozincs R 1 R 2 Zn, mixed diorganocuprates R 1 R 2 CuM (M = MgBr, ZnCl) and Cu‐catalyzed mixed triorganozincates R 1 (R 2 ) 2 ZnMgBr depends on the reaction parameters, such as solvent and catalyst. They also developed new atom‐economic procedures for C–alkyl, C–N and C–acyl coupling reactions using mixed diorganozincs R R R T Zn.…”

Reactivity of mixed organozinc and mixed organocopper reagents: 14. Phosphine-nickel catalyzed aryl-allyl coupling of (n-butyl)(aryl)zincs. Ligand and substrate control on the group selectivity and regioselectivity

“…Theoretical studies on the control of group selectivity have been reported by Nakamura [32,33] and experimental studies on the effects of organyl groups on the reactivity and selectivity of mixed cuprates have been reported by Bertz [34] and Nakamura [35]. Our group carried out a series of synthetic and mechanistic work [36e40] on the reactivity and group selectivity of mixed diorganozincs, R 1 R 2 Zn [36]; mixed diorganocuprates, R 1 R 2 CuM (M ¼ MgBr [37], ZnCl [38]) and Cu catalyzed mixed triorganozincates, R 1 (R 2 ) 2 ZnMgBr [38] in their CeC [36], C-COR [39], C-COOR [38] and CeN coupling [40] reactions. We showed that the group selectivity of both mixed diorganocuprates and diorganozincs can be controlled by changing reaction parameters, i.e.…”

Reactivities of mixed organozinc and mixed organocopper reagents. Part 13 Kinetic study for phosphine‐catalyzed acylation of alkylarylzincs and effect of residual group on the transfer rate of alkyl group

“…In their systematic work, Erdik and coworkers observed that the group selectivities of mixed diorganocuprates, R 1 R 2 CuM (MMgBr), ZnI, diorganozincs, R 1 R 2 Zn, and Cu‐catalyzed mixed triorganozincates, R 1 (R 2 ) 2 ZnMgBr, depend on the reaction parameters, that is, the electrophilic substrate, the solvent, and the temperature as well as the transition metal catalyst and organocatalyst, and reported that the group selectivity of mixed organocopper and organozinc reagents can be controlled by changing the reaction parameters. They also developed new atom‐economic synthetic procedures for CC, C‐acyl, and CN coupling employing mixed arylzinc reagents. However, probing the origin of group selectivity in the mixed organocopper and organozinc reagents still seems a problem.…”