Palladium Enolate Umpolung: Cyclative Diacetoxylation of Alkynyl Cyclohexadienones Promoted by a Pd/SPRIX Catalyst
作者:Kazuhiro Takenaka、Suman C. Mohanta、Hiroaki Sasai
DOI:10.1002/anie.201311172
日期:2014.4.25
A novel palladium‐catalyzed reaction involving an unusual nucleophilic attack on a palladiumenolate was developed using a spiro‐bis(isoxazoline) (SPRIX) ligand. Treatment of alkynylcyclohexadienone substrates with a Pd/SPRIXcatalyst in acetic acid under an oxygen atmosphere furnished diacetoxylated benzofuranone derivatives in good yields. This cyclativediacetoxylation proceeded enantioselectively
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
Ligand and substrate effects during Pd-catalyzed cyclizations of alkyne-tethered cyclohexadienones
作者:Rodolfo Tello-Aburto、Kyle A. Kalstabakken、Andrew M. Harned
DOI:10.1039/c3ob27491h
日期:——
The effects of ligand and substrate choice on the Pd-catalyzed cyclization of alkyne-tethered cyclohexadienones were examined. In the presence of a chiral ligand, the enantioselectivity of the desymmetrization is remarkably sensitive to structural changes in both the ligand and the substrate. Additionally, the regioselectivity of the reaction (5- vs. 6-memberedringformation) is dependent on the proximity
rhodium(I)-BINAP-catalyzed highlyenantioselective [2+2+2] cycloaddition of enynes with alkynes has been developed. Diverse fused tricyclic hydronaphthofuran scaffolds with three consecutive stereogenic centers were constructed in onestep from easily available materials with excellent chemo-, regio-, diastereo-, and enantioselectivity. Notable features of these reactions include 100 % atom economy
Palladium-catalyzed desymmetric [2+2+2] cycloaddition of 1,6-enyne and alkyne
作者:Wei-Cheng Zhao、Xin Wang、Juhua Feng、Ping Tian、Zhi-Tao He
DOI:10.1016/j.tet.2020.131862
日期:2021.1
desymmetric [2+2+2] cycloaddition reaction of alkyne-tethered cyclohexadienone and internal alkyne is established. Widely existing fused tricyclic hydronaphthofuran and hydronaphthopyrrole frameworks are prepared diastereoselectively in moderate to excellent yields. One-step aromatization process provides a new and facile access to important benzene-containing tricycles from above cycloaddition products