An efficient, nickel-catalyzed direct reductive cross-coupling of equimolar amounts of alkyl halides with aryl halides in the presence of manganese is generally high-yielding, highly functional-group-tolerant, and easy to perform. The reaction appears to avoid the formation of intermediate organomanganese species, and a synergistic effect was found when a mixture of two ligands was employed.
D. A. Everson, R. Shrestha, D. J. Weix, J. Am. Chem. Soc., 2010, 132, 920-921.
A direct cobalt-catalyzed vinylation of various aromatic halides using β-halostyrene proceeded smoothly with a total retention of the double bond configuration in the presence of triphenylphosphine as ligand. This procedure offers a new route to the stereoselective synthesis of functionalized stilbenes.
A. Moncomble, P. Le Floch, A. Lledos, C. Gosmini, J. Org. Chem., 2012, 77, 5056-5062.
A Ni-catalyzed asymmetric reductive cross-coupling between vinyl bromides and benzyl chlorides provides direct access to enantioenriched products bearing aryl-substituted tertiary allylic stereogenic centers from simple, stable starting materials. A broad substrate scope can be converted under mild reaction conditions without pregeneration of organometallic reagents and the regioselectivity issues commonly associated with allylic arylation.
A. H. Cherney, S. E. Reisman, J. Am. Chem. Soc., 2014, 136, 14365-14366.
A nickel-catalyzed carboxylation of aryl and vinyl chlorides proceeds under a CO2 pressure of 1 atm at room temperature in the presence of nickel catalysts and Mn powder as a reducing agent. Various aryl chlorides and vinyl chlorides could be converted to the corresponding carboxylic acid in good yields.
T. Fujihara, K. Nogi, T. Xu, J. Terao, Y. Tsuji, J. Am. Chem. Soc., 2012, 134, 9106-9109.
A user-friendly and operationally simple Ni-catalyzed carboxylation of unactivated primary alkyl bromides and sulfonates with CO2 at atmospheric pressure is characterized by its mild conditions and remarkably wide scope without the need for air- or moisture-sensitive reagents.
Y. Liu, J. Cornella, R. Martin, J. Am. Chem. Soc., 2014, 136, 11212-11215.
A catalytic carboxylation of unactivated primary, secondary, and tertiary alkyl chlorides with CO2 at atmospheric pressure features exquisite chemoselectivity, mild conditions and ease of execution.
M. Börjesson, T. Moragas, R. Martin, J. Am. Chem. Soc., 2016, 138, 7504-7507.
A highly efficient cobalt-catalyzed reductive carboxylation reaction of alkenyl trifluoromethanesulfonates (triflates) enables the synthesis of α,β-unsaturated carboxylic acids in the presence of Mn powder as a reducing reagent under 1 atm pressure of CO2 at room temperature. Moreover, the carboxylation of sterically hindered aryl triflates proceeds smoothly in the presence of a nickel or cobalt catalyst.
K. Nogi, T. Fujihara, J. Terao, Y. Tsuji, J. Org. Chem., 2015, 80, 11618-11623.
A simple, chemoselective Ni-catalyzed reductive cyclization/carboxylation of unactivated alkyl halides with CO2 operates under mild conditions.
X. Wang, Y. Liu, R. Martin, J. Am. Chem. Soc., 2015, 137, 6476-6479.
Unsymmetrical dialkyl ketones can be prepared by the nickel-catalyzed reductive coupling of carboxylic acid chlorides or (2-pyridyl)thioesters with alkyl iodides or benzylic chlorides. Various functional groups are tolerated, including common nitrogen protecting groups and C-B bonds. Even hindered ketones flanked by tertiary and secondary centers can be formed.
A. C. Wotal, D. J. Weix, Org. Lett., 2012, 14, 1363-1365.
An enantioselective Ni-catalyzed reductive cross-coupling of acid chlorides with racemic secondary benzyl chlorides in the presence of Mn0 as a stoichiometric reductant generates acyclic α,α-disubstituted ketones in good yields and high enantioselectivity. The mild, base-free reaction conditions tolerate various functional groups on both coupling partners.
A. H. Cherney, N. T. Kadunce, S. E. Reisman, J. Am. Chem. Soc., 2013, 135, 7442-7445.
A mild and user-friendly Ni-catalyzed regioselective hydrocarboxylation enables a regioselective conversion of a broad range of alkynes with CO2 (1 bar) while obviating the need for sensitive organometallic species and using simple alcohols as proton sources.
X. Wang, M. Nakajima, R. Martin, J. Am. Chem. Soc., 2015, 137, 8924-8927.
A generally applicable, sequential reaction of dichloroesters with various aldehydes is promoted by active manganese to give α,β-unsaturated esters with complete control of stereoselectivity. The C-C double bond can be di- or trisubstituted. A mechanism based on a successive aldol-type reaction/-elimination is proposed.
J. M. Concellón, H. Rodríquez-Solla, P. Díaz, R. Llaona, J. Org. Chem., 2007, 72, 4396-4400.
A complete E-selective synthesis of α,β-unsaturated amides through a sequential reaction of a range of dichloroamides with a variety of aldehydes is promoted by Rieke manganese (Mn*). The unsaturated amides obtained are readily and efficiently transformed into α,β-unsaturated ketones, aldehydes, or carboxylic acids.
J. M. Concellón, H. Rodríquez-Solla, P. Díaz, J. Org. Chem., 2007, 72, 7974-7979.
Stereoselective β-elimination of diastereomeric mixtures of 2-bromo-3-hydroxyesters is achieved by using unactivated manganese and trimethylsilyl chloride, to yield (E)-α,β-unsaturated esters with total diastereoselectivity.
J. M. Concellón, H. Rodríguez-Solla, V. del Amo, Synlett, 2006, 315-317.
A totally regioselective transformation of aromatic N-4-methoxyphenylaziridine 2-carboxamides into 2-aminoamides is promoted by active manganese (Mn*). α-Amino ketones can be readily obtained by reaction of morpholine-derived 2-aminoamides with organolithium compounds.
J. M. Concellón, H. Rodríguez-Solla, V. del Amo, P. Díaz, J. Org. Chem., 2010, 75, 2407-2410.