Fused ring aziridines as a facile entry into triazole fused tricyclic and bicyclic heterocycles
作者:Fang Fang、Megan Vogel、Jennifer V. Hines、Stephen C. Bergmeier
DOI:10.1039/c2ob07042a
日期:——
alkyne has provided a useful entry into triazole fused tricyclic heterocycles containing both the triazole ring and the oxazolidin-2-one ringsystem. The requisite azido-alkynes have been prepared via a two-step sequence from fused ring aziridines. A series of 6–12 membered rings containing both the oxazolidinone and triazole rings have been prepared. These ringsystems have been designed as conformationally
Highly Enantioselective Rhodium-Catalyzed Cross-Addition of Silylacetylenes to Cyclohexadienone-Tethered Internal Alkynes
作者:Chang-Lin Duan、Yun-Xuan Tan、Jun-Li Zhang、Shiping Yang、Han-Qing Dong、Ping Tian、Guo-Qiang Lin
DOI:10.1021/acs.orglett.9b00249
日期:2019.3.15
The first highlyenantioselective rhodium-catalyzed cross-addition of silylacetylenes to cyclohexadienone-tethered internal alkynes has been achieved via a tandem process: regioselective alkynylation of the internal alkynes and subsequent intramolecular conjugateaddition to the cyclohexadienones, affording the cis-hydrobenzofuran frameworks with good yields (up to 88% yield) and excellent enantioselectivities
Effective synthesis of bicyclodienes via palladium-catalyzed asymmetric allylic alkylation and ruthenium-catalyzed cycloisomerization
作者:Nizam HAVARE
DOI:10.3906/kim-2004-81
日期:——
[n.3.0]Bicycles (n = 3–6) can be synthesized using palladium-catalyzed asymmetric allylic alkylation followed by ruthenium-catalyzedcycloisomerization. New types of triarylphosphino-1,2-diaminooxazoline ligands show the same high levels of enantioselectivity observed with Trost ligand when employed in Pd-catalyzed allylic alkylation reactions. The enyne products of these allylic alkylation reactions
Asymmetric Total Synthesis of Sarpagine-Related Indole Alkaloids Hydroxygardnerine, Hydroxygardnutine, Gardnerine, (<i>E</i>)-16-<i>epi</i>-Normacusine B, and Koumine
Sarpagine-related indole alkaloids (−)-hydroxygardnerine, (+)-hydroxygardnutine, (−)-gardnerine, (+)-(E)-16-epi-normacusine B, and (−)-koumine were divergently synthesized via a common intermediate possessing a piperidine ring with an exocyclic (E)-ethylidene side chain, which was constructed by a gold(I)-catalyzed 6-exo-dig cyclization strategy.
The title compound, C42H34O2, crystallizes in the space group R (3) over bar with one molecule disordered at a crystallographic (3) over bar site and another in a general position, The conformation of the linkage of the trityl groups to the central butyne group is such that the O-C ... C-O grouping forms a torsion angle of magnitude 87.2(2)degrees. The C=C length in the ordered molecule is 1.176(3) Angstrom.