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Suppression of β‐Hydride Elimination in the Intramolecular Hydrocarboxylation of Alkynes leading to the Formation of Lactones
Author(s) -
Huo Zhibao,
Patil Nitin T.,
Jin Tienan,
Pahadi Nirmal K.,
Yamamoto Yoshinori
Publication year - 2007
Publication title -
advanced synthesis and catalysis
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.541
H-Index - 155
eISSN - 1615-4169
pISSN - 1615-4150
DOI - 10.1002/adsc.200600507
Subject(s) - chemistry , intramolecular force , catalysis , palladium , medicinal chemistry , toluene , hydride , diene , carboxylic acid , organic chemistry , hydrogen , natural rubber
Abstract Palladium‐catalyzed intramolecular cyclization of the alkynoic acids was studied which gave the five‐ and six‐membered lactones in moderate yields. The reaction can be conducted simply by heating a toluene solution of alkynoic acids at 100 °C in the presence of catalytic amounts of Pd(PPh 3 ) 4 and ( o ‐tol) 3 P. The key for this transformation is the use of phosphines, instead of carboxylic acids, as an additive. Similar to our previously developed catalytic system the use of carboxylic acid, instead of ( o ‐tol) 3 P, resulted into the exclusive formation of the diene.