Palladium-Catalyzed Benzylation of Heterocyclic Aromatic Compounds
作者:David Lapointe、Keith Fagnou
DOI:10.1021/ol901689q
日期:2009.9.17
Broadly applicable palladium-catalyzed heteroarene benzylation reactions are described with a focus on the most challenging heterocyclic classes under traditional benzylation techniques such as sulfur-containing heterocycles and those bearing functional groups that would be incompatible with reactions requiring Lewis acids and/or strong bases.
[reaction: see text] 2,5-Disubstituted oxazoles have been prepared through the reaction of N-propargylamides with aryl iodides in the presence of Pd(2)(dba)(3), tri(2-furyl)phosphine, and NaO(t)()Bu. The reaction appears to proceed through a palladium-catalyzed coupling step followed by the in situ cyclization of the resultant coupling product.
Synthesis of 2-Aryl- and 5-Alkyl-2-aryloxazoles from 2-Aryl-5-bromooxazoles
作者:Choji Kashima、Hideki Arao
DOI:10.1055/s-1989-27419
日期:——
2-Aryloxazoles, their 5-deuterio derivatives, and 5-alkyl-2-aryloxazoles are prepared in good yields from 2-aryl-5-bromooxazoles via halogen/metal exchange with butyllithium followed by treatment with water, methanol-O-d, or alkyl halides, respectively.
Synthesis of Substituted Oxazoles from<i>N</i>-Benzyl Propargyl Amines and Acid Chlorides
作者:Henrik v. Wachenfeldt、Filip Paulsen、Anders Sundin、Daniel Strand
DOI:10.1002/ejoc.201300285
日期:2013.7
The reaction between N-benzylpropargylamines and acid chlorides at elevated temperatures provides efficient, direct access to a variety of di- and tri-substituted oxazoles. The versatility of this reaction is explored and 21 examples are demonstrated. The usefulness of the methodology is showcased through the short and efficient formal syntheses of medicinally relevant drugs aleglitazar and romazarit
Catalytic Three-Component Domino Reaction for the Preparation of Trisubstituted Oxazoles
作者:Henrik v. Wachenfeldt、Philipp Röse、Filip Paulsen、Nagarajan Loganathan、Daniel Strand
DOI:10.1002/chem.201300019
日期:2013.6.10
end, an efficient gold‐catalyzed three‐component domino reaction to form oxazoles directly from imines, alkynes, and acid chlorides is presented. The reaction proceeds in a single synthetic step by using a gold(III)–N,N′‐ethylenebis(salicylimine) (salen) catalyst to give trisubstituted oxazoles in up to 96 % yield. The substrate scope, a mechanistic study exploring the role of the gold catalyst, and the