Controlled and Chemoselective Reduction of Secondary Amides
作者:Guillaume Pelletier、William S. Bechara、André B. Charette
DOI:10.1021/ja105194s
日期:2010.9.22
presence of 2-fluoropyridine. The electrophilic activated amide can then be reduced to the corresponding iminium using triethylsilane, a cheap, rather inert, and commercially availablereagent. Imines can be isolated after a basic workup or readily transformed to the aldehydes following an acidic workup. The amine moiety can be accessed via a sequential reductive amination by the addition of silane and
Directed functionalization of 1,2-dihydropyridines: stereoselective synthesis of 2,6-disubstituted piperidines
作者:Guillaume Pelletier、Léa Constantineau-Forget、André B. Charette
DOI:10.1039/c4cc02220c
日期:——
A practical and highly stereoselective approach to access 2,6-disubstituted piperidines using an amidine auxiliary is reported. Following the diastereoselective addition of Grignard reagents at the 2-position of an activated pyridinium salt, the amidine group directs a regioselective metalation at the 6-position, enabling further functionalization. A subsequent electrophilic quench or a Negishi cross-coupling
Nucleophilic Addition to 3-Substituted Pyridinium Salts: Expedient Syntheses of (−)-L-733,061 and (−)-CP-99,994
作者:Alexandre Lemire、Michel Grenon、Mehrnaz Pourashraf、André B. Charette
DOI:10.1021/ol048624n
日期:2004.9.1
[reaction: see text] The addition of nucleophiles to 3-substituted pyridinium salts prepared from N-methylbenzamide and various pyridines has been investigated. Good to excellent regioselectivities favoring the 2,3-disubstituted 1,2-dihydropyridines were observed. The resulting 1,2-dihydropyridines led to the corresponding 2,3-disubstituted pyridines upon treatment with Mn(OAc)3/NaIO4. This methodology
A novel approach to β‐enaminones has been developed, based on a Tf2O‐mediated reaction of secondaryamides with ketonesenamines. The method can be extended to the one‐pot condensation of secondaryamides with ketones for β‐enaminones synthesis.
Mild Method for the Conversion of Amides to Thioamides
作者:André B. Charette、Michel Grenon
DOI:10.1021/jo0344485
日期:2003.7.1
Aqueous ammonium sulfide was found to be an ideal substitute for hydrogen sulfide for the thiolysis of activated amides. High yields of the corresponding thioamides were obtained for a broad range of substrates, using two different procedures that are both operationally simple and inexpensive, as well as amenable to large-scale preparation. Preliminary results indicate that aqueous ammonium sulfide