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Copper‐Free Sonogashira Coupling of Acid Chlorides with Terminal Alkynes in the Presence of a Reusable Palladium Catalyst: An Improved Synthesis of 3‐Iodochromenones (=3‐Iodo‐4 H ‐1‐benzopyran‐4‐ones)
Author(s) -
Likhar Pravin R.,
Subhas M. S.,
Roy Moumita,
Roy Sarabindu,
Kantam M. Lakshmi
Publication year - 2008
Publication title -
helvetica chimica acta
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.74
H-Index - 82
eISSN - 1522-2675
pISSN - 0018-019X
DOI - 10.1002/hlca.200890032
Subject(s) - chemistry , sonogashira coupling , catalysis , palladium , cerium , yield (engineering) , ammonium nitrate , copper , palladium catalyst , medicinal chemistry , alkyne , organic chemistry , materials science , metallurgy
Pd/C is used as an efficient catalyst for the copper‐free Sonogashira coupling of acid chlorides and terminal alkynes to afford ynones in high yields ( Tables 1 and 3 ). Cyclization of (2‐methoxyaryl)‐substituted ynones induced by I 2 /ammonium cerium(IV) nitrate (CAN) at room temperature gave 3‐iodochromenones (=3‐iodo‐4 H ‐1‐benzopyran‐4‐ones) in excellent yield ( Table 4 ).