Enantioselective Synthesis of 4-Substituted Dihydrocoumarins through a Zinc Bis(hydroxyamide)-Catalyzed Conjugate Addition of Terminal Alkynes
作者:Gonzalo Blay、M. Carmen Muñoz、José R. Pedro、Amparo Sanz-Marco
DOI:10.1002/adsc.201201120
日期:2013.4.15
A new enantioselective catalyst for the conjugateaddition of terminalalkynes has been developed. Terminalalkynes react with 3‐alkoxycarbonylcoumarins in the presence of diethylzinc and bis(hydroxyamide) ligands to give chiral non‐racemic dihydrocoumarins substituted with an alkynyl group on the C‐4 position with good yields and enantiomeric excesses up to 95%.
Synthesis of Coumarines and 4<i>H</i>-Chromenes through the Reaction of<i>tert</i>-Butyl Isocyanide and Dialkyl Acetylenedicarboxylates in Presence of 2-Hydroxybenzaldehydes
作者:Issa Yavari、Hoorieh Djahaniani、Farough Nasiri
DOI:10.1055/s-2004-815990
日期:——
An effective route to novel coumarines and 4H-chromenes is described. This involves the reaction of tert-butyl isocyanide and dialkyl acetylenedicarboxylates in the presence of 2-hydroxybenzaldehydes.