Categories: Synthesis of O-Heterocycles > Lactones >
Synthesis of 3,4-dihydropyran-2-ones
Recent Literature
Ring-closing metathesis of unsaturated carboxylic acids vinyl esters enables
an efficient synthesis of endocyclic enol lactones. The developed methodology
offers an easy route for synthetically challenging target molecules with
different functional groups and substitution. Vinyl esters of cyclic carboxylic
acids can also be successfully applied for domino ring-opening ring-closing
metathesis sequences.
A. Brodzka, F. Borys, D. Koszelewski, R. Ostaszewski, J. Org. Chem., 2018, 83,
8655-8661.
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 (NHC)-catalyzed highly enantioselective lactonization
of modified enals with enolizable aldehydes proceeds via α,β-unsaturated
acylazolium intermediates and yields synthetically important 4,5-disubstituted
dihydropyranones.
S. R. Yetra, T. Kaicharla, S. S. Kunte, R. G. Gonnade, A. T. Biju, Org. Lett., 2013,
15, 5202-5205.
Asymmetric Michael addition-lactonization reactions of β,γ-unsaturated α-keto
esters with thioesters catalyzed by a proline-derived urea provide
3,4-dihydropyranones and spiro-3,4-dihydrocoumarin-fused 3′,4′-dihydropyranones
in high yield with excellent stereoselectivities via bioinspired S-to-O
acyl-transfer reactions.
H. Jin, J. Lee, H. Shi, J. Y. Lee, E. J. Yoo, C. E. Song, D. H. Ryu, Org. Lett.,
2018, 20, 1584-15888.