Synthesis of lactams and related compounds
An oxidative copper-catalyzed arylation of various ring-size lactams with arylboronic acids gives N-arylated products in good yield without any additional bases, ligands, or additives.
T. Bathini, V. S. Rawat, B. Sreedhar, Synlett, 2015, 26, 1348-1351.
A quick, efficient, one-pot, BF3·OEt2-mediated reaction of various substituted arenes with azido alkanoic acid chlorides affords substituted N-aryl lactams in good to excellent yields at room temperature.
D. Caturvedi, A. K. Chaturvedi, N. Mishra, V. Mishra, Synlett, 2012, 23, 2627-2630.
The reaction of amide and thioamide dianions with epibromohydrin resulted in regioselective formation of 5-(hydroxymethyl)pyrrolidin-2-ones (pyroglutaminols) and -thiones.
I. Freifeld, H. Armbrust, P. Langer, Synthesis, 2006, 1807-1808.
An intramolecular vinylation of various iodoenamides using CuI as the catalyst and N,N'-dimethylethylenediamine as the ligand led to five- to seven-membered lactams in moderate to excellent yields.
T. Hu, C. Li, Org. Lett., 2005, 7, 2035-2038.
Optically enriched N-fused bicyclic amides and small- and medium-ring unsaturated cyclic amines can be synthesized in up to 98% ee through Mo-catalyzed desymmetrization of readily available achiral polyene substrates. The effects of catalyst structure, olefin substitution, positioning of Lewis basic functional groups and ring size are examined and discussed in detail.
E. S. Sattely, G. Alexander Cortez, D. C. Moebius, R. R. Schrock, A. H. Hoveyda, J. Am. Chem. Soc., 2005, 127, 8526-8533.
ROM-RCM of cyclobutenylmethylamines having an alkyne moiety in a tether afforded isoquinoline derivatives in good yields using a second-generation Grubbs catalyst.
M. Mori, H. Wakamatsu, K. Tonogaki, R. Fujita, T. Kitamura, Y. Sato, J. Org. Chem., 2005, 70, 1066-1069.
Organic azides are easily and chemoselectively reduced to the corresponding amines by reaction with dichloroindium hydride under very mild conditions. γ-Azidonitriles give pyrrolidin-2-imines in an outstanding cyclization.
L. Benati, G. Bencivenni, R. Leardini, D. Nanni, M. Minozzi, P. Spagnolo, R. Scialpi, G. Zanardi, Org. Lett., 2006, 8, 2499-2502.
After NHC-catalyzed activation of acetic esters, the catalytically generated triazolium enolate intermediates serve as two-carbon nucleophiles that undergo highly enantioselective reactions with enones and α,β-unsaturated imines to give α-unsubstituted δ-lactones and lactams, respectively.
S. Chen, L. Hao, Y. Zhang, B. Tiwari, Y. R. Chi, Org. Lett., 2013, 15, 5822-5825.
An N-heterocyclic carbene-catalyzed oxidative LUMO activation of the β-carbons of saturated carboxylic esters enables an efficient asymmetric access to lactams and lactones. The method introduces functional groups at the typically inert β-sp3 carbons of saturated esters. The use of HOBt as an additive improves both yields and enantioselectivities of the reactions.
B. Liu, W. Wang, R. Huang, J. Yan, J. Wu, W. Xue, S. Yang, Z. Jin, Y. R. Chi, Org. Lett., 2018, 20, 260-263.