Mild Regiospecific Synthesis of 1-Alkoxy-isochromenes Catalyzed by Well-Defined [Silver(I)(Pyridine-Containing Ligand)] Complexes
摘要:
The synthesis of 3-substituted-1-alkoxyisochromenes starting from 2-alkynylbenzaldehydes and different alcohols is reported. The reaction is catalyzed by a silver(1) complex with an original macrocyclic pyridine-containing ligand. The approach is characterized by absolute regioselectivity, mild reaction conditions, good to excellent reaction yields, cleanness of the reaction, and reduced purification steps. The reaction mechanism was investigated by in-depth H-1 NMR experiments and an aimed "trapping" experiment.
Copper Catalyzed Enantioselective Alkylation of Pyrrole with β,γ-Unsaturated α-Ketoesters: Application to One-Pot Construction of the Seven-Membered Ring by Merging a Gold Catalysis
作者:Yanbin Hu、Yanan Li、Sheng Zhang、Chong Li、Lijun Li、Zhenggen Zha、Zhiyong Wang
DOI:10.1021/acs.orglett.5b01917
日期:2015.8.21
A highly enantioselective Friedel Crafts alkylation of pyrrole to beta,gamma-unsaturated alpha-ketoesters was developed by virtue of a chiral copper complex, affording the alkylated derivatives of pyrrole with good yields and excellent enantioselectivities. Moreover, merging copper catalysis with gold catalysis realized a one-pot construction of the seven-membered ring to give annulated pyrroles with moderate to good yields and high enantiomeric excesses.
Stepwise Delivery of Two Methoxy Groups of Arylaldehyde Acetals across the Phenyl Ring. Vacant Site-Controlled Palladium Catalysis
作者:Itaru Nakamura、Yuya Mizushima、Ilya D. Gridnev、Yoshinori Yamamoto
DOI:10.1021/ja051114j
日期:2005.7.13
A new catalytic cyclization of o-alkynylbenzaidehyde acetals 1 to the functionalized indenes 2 was found to be strictly controlled by the number of triphenylphosphine ligands on the Pd catalyst. Only complexes with three available coordination sites on Pd catalyze this reaction. Mechanistic study suggests that pi-coordination of Pd to the benzene ring is a key step controlled by the number of vacant coordination sites.