Synthesis of S-Heterocycles
An efficient reaction of carbon disulfide with oxiranes in the presence of sodium hydride (10 mol%) and methanol gives functionalized 1,3oxathiolane-2-thiones in very good yields.
I. Yavari, M. Ghazanfarpour-Darjani, Z. Hossaini, M. Sabbaghan, N. Hosseini, Synlett, 2008, 889-891.
A mild reaction of α,α-difluoroalkyl amines with β-amino alcohols, β-amino thiols, and β-diamines affords the corresponding oxazoline, thiazoline, and imidazoline derivatives, respectively. The conditions are applicable for the synthesis of optically active heterocyclic compounds.
T. Fukuhara, C. Hasegawa, S. Hara, Synthesis, 2007, 1528-1534.
A highly efficient and stereoselective gold-catalyzed cycloisomerization of α-thioallenes to 2,5-dihydrothiophenes has been discovered.
N. Morita, N. Krause, Angew. Chem. Int. Ed., 2006, 45, 1897-1899.
With CuI as the catalyst and K3PO4 • 3 H2O as the base, a highly efficient, ligand-free intramolecular S-vinylation of thiols with vinyl chlorides or bromides was successfully implemented. Moreover, competition experiments revealed that the 4-exo cyclization is fundamentally preferred over other modes (5-exo, 6-exo, and 6-endo) of cyclization.
Q. Zhao, L. Li, Y. Fang, D. Sun, C. Li, J. Org. Chem., 2009, 74, 459-462.
Starting from readily available o-mercaptoacylphenones, a mild S-nitrosation and a subsequent intramolecular aza-Wittig reaction lead to the construction of 3-substituted benzisothiazoles.
N. O. Devarie-Baez, M. Xian, Org. Lett., 2010, 12, 752-754.
The reaction of o-haloaniline derivatives and carbon disulfide in the presence of 1,8-diazabicyclo[5.4.0]undec-7-ene at 80-140˚C provides the corresponding 1,3-benzothiazole-2(3H)-thione derivatives in good yields.
Y. Fu, X. Hu, Y. Chen, Y. Yang, H. Hou, Y. Hu, Synthesis, 2012, 1477-1480.
Sequential coupling-imination-annulation reactions of ortho-bromoarylaldehydes and terminal alkynes with ammonium acetate in the presence of a palladium catalyst under microwave irradiation gives various substituted isoquinolines, furopyridines, and thienopyridines in good yields.
D. Yang, S. Burugupalli, D. Daniel, Y. Chen, J. Org. Chem., 2012, 77, 4466-4472.
A mild ICl-induced cyclization of heteroatom-substituted alkynones provides a simple, highly efficient approach to various 3-iodochromones, iodothiochromenones, iodoquinolinones and analogues in good to excellent yields. Subsequent palladium-catalyzed transformations afford a rapid increase in molecular complexity.
C. Zhou, A. V. Dubrovsky, R. C. Larock, J. Org. Chem., 2006, 71, 1626-1632.