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One–pot Selective Synthesis of 2,3‐Dihydro‐4 H ‐Furo[3,2‐ c ]coumarins by Palladium‐Catalyzed Silver‐Assisted Propargylation/Intramolecular 5‐ exo– dig Cyclization
Author(s) -
Uchiyama Chihiro,
Miyadera Yukari,
Hayashi Yoshio,
Yakushiji Fumika
Publication year - 2017
Publication title -
chemistryselect
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.437
H-Index - 34
ISSN - 2365-6549
DOI - 10.1002/slct.201700475
Subject(s) - palladium , regioselectivity , chemistry , alkyne , catalysis , triphenylphosphine , propargyl , medicinal chemistry , intramolecular force , furocoumarins , combinatorial chemistry , organic chemistry , photochemistry
A new catalytic system using bis(triphenylphosphine)palladium(II) dichloride and Ag 2 CO 3 was developed for the one‐pot selective synthesis of dihydrofuro[3,2‐ c ]coumarin 3 from 4‐hydroxycoumarin ( 1 ) and propargylic carbonate 2 under the mild condition. Our catalytic system afforded distinct regioselectivity compared to reported methodologies using palladium catalysts, 2 and active methylene compounds. In addition, furo[3,2‐ c ]coumarin 4 was derived from 3 with Et 3 N. The proposed reaction mechanism involved 4‐hydroxycoumarin ( 1 ) reacting with the η 1 –(propargyl)palladium complex to generate a terminal alkyne, and subsequent intramolecular 5‐ exo ‐dig cyclization selectively synthesized 3 in one‐pot. The newly developed methodology is beneficial in the construction of a novel compound library related to furocoumarins with distinct regioselective preference.