The reaction between aryl- or vinylboroxines with α-diazocarbonyl compounds offers an alternative approach for α-arylation and α-vinylation of carbonyl compounds. α-Arylated or α-vinylated carbonyl compounds are formed under mild conditions.
C. Peng, W. Zhang, G. Yan, J. Wang, Org. Lett., 2009, 11, 1667-1670.
A synergistic combination of copper and chiral amine catalysis enables an enantioselective α-vinylation of aldehydes using vinyl iodonium triflate salts. These mild catalysis provides enolizable α-formyl vinylic stereocenters without racemization or olefin transposition. These high-value coupling adducts are readily converted into various useful olefin synthons.
E. Skucas, D. W. C. MacMillan, J. Am. Chem. Soc., 2012, 134, 9090-9093.
A synergistic combination of copper and chiral amine catalysis enables an enantioselective α-alkenylation of aldehydes using boronic acids. The merger of two highly utilized and robust catalytic systems has allowed for the development of a mild and operationally trivial protocol for the direct formation of α-formyl olefins employing common building blocks for organic synthesis.
J. M Stevens. D. W. C. MacMillan, J. Am. Chem. Soc., 2013, 135, 11756-11757.
The use of gem-bis(boronates) as precursors enables a construction of quaternary α-aryl aldehydes, in which both groups are installed simultaneously. This methodology provides a general strategy to produce quaternary α-aryl aldehydes with broad scopes and synthetic convenience. In addition, gem-bis(boronates) are readily available from ketones.
P. Zheng, Y. Zhai, X. Zhao, T. Xu, Org. Lett., 2019, 21, 393-396.
Intermolecular coupling of aromatic and aliphatic ketone lithium enolates with a variety of alkenyl halides is achieved in good yields in the presence of Ni(cod)2 catalyst, an N-heterocyclic carbene (NHC) ligand, and LiI.
M. Grigalunas, T. Ankner, P.-O. Norrby, O. Wiest, P. Helquist, J. Am. Chem. Soc., 2015, 137, 7019-7022.
In a protocol for a mild, catalytic, intermolecular alkenylation of ketone enolates, Pd/Q-Phos as catalyst enables an efficient intermolecular coupling of various ketones with alkenyl bromides with a slight excess of LiHMDS at 0°C.
M. Grigalunas, T. Ankner, P.-O. Norrby, O. Wiest, P. Helquist, Org. Lett., 2014, 16, 3970-3973.
KOtBu/DMSO promoted α-vinylation of aliphatic, cycloaliphatic, and alkyl aromatic (heteroaromatic) ketones with diverse arylacetylenes enables the synthesis of various β,γ-unsaturated ketones of E configuration in very good yields.
B. A. Trofimov, E. Y. Schmidt, N. V. Zorina, E. V. Ivanova, I. A. Ushakov, J. Org. Chem., 2012, 77, 6880-6886.
A radical alkenylation reaction of α-halo carbonyl compounds with styrylindium dichloride as well as unactivated alkenylindiums proceeded in the presence of triethylborane. The geometry of the carbon-carbon double bonds was retained. Efficient one-pot strategies were developed.
K. Takami, H. Yorimitsu, K. Oshima, Org. Lett., 2004, 6, 4555-4558.
A convenient and general atom transfer radical addition (ATRA) of simple nitriles, ketones, and esters to alkynes provides a wide range of β,γ-unsaturated nitriles, ketones, and esters.
Y. Xiao, Z.-Q. Liu, Org. Lett., 2019, 21, 8810-8813.
Multifunctional palladium catalysis allows a one-pot stereocontrolled synthesis of tetrasubstituted methyl ketones and enynes. The homogeneous palladium dihalide catalyst is used for the bromo-/chloroallylation of alkynes and in situ for subsequent Wacker-Tsuji oxidation or Sonogashira cross-coupling.
A. N. Thadani, V. H. Rawal, Org. Lett., 2002, 4, 4321-4323.