Oxidative decar☐ylation of α-amino acids: A mild and efficient method for the generation ofN-acyliminium ions
作者:Alicia Boto、Rosendo Herna´ndez、Ernesto Sua´rez
DOI:10.1016/s0040-4039(99)01180-6
日期:1999.8
The oxidative decar☐ylation of α-amino acids using the system (diacetoxyiodo)benzene or iodosylbenzene and iodine proceeded smoothly at room temperature. The intermediacy of anN-acyliminium cation has been demonstrated through intermolecular and intramolecular trapping with nucleophiles.
Tandem Radical Decarboxylation−Oxidation of Amino Acids: A Mild and Efficient Method for the Generation of <i>N</i>-Acyliminium Ions and Their Nucleophilic Trapping
作者:Alicia Boto、Rosendo Hernández、Ernesto Suárez
DOI:10.1021/jo000356t
日期:2000.8.1
derivatives have been prepared in order to test the scope and diastereoselectivity of this method. These substrates were treated with iodosylbenzene or (diacetoxyiodo)benzene (DIB) and iodine in order to generate the corresponding carboxyl radical, which evolves by loss of carbon dioxide to produce a carbon radical which in turn undergoes oxidation to an N-acyliminium ion. This postulated intermediate
The Dakin-West Reaction of N-Acylprolines in the Presence of Inorganic Bases: Unexpected Formation of Enol Esters
作者:Masami Kawase、Momoko Saeki、Yuri Hagimoto、Hidemitsu Uno
DOI:10.3987/com-08-s(d)50
日期:——
novel transformation of N-acylprolines (1) to enol esters (2) was realized by utilizing chlorodifluoroacetic or trifluoroacetic anhydrides in the presence of inorganic bases, in which probableintermediates were mesoionic 1,3-oxazolium-5-olates. The structure of the enol ester (2a) was determined by single crystal X-ray analysis.
A General Method for the Preparation of 5-Trifluoromethylated Oxazoles from .ALPHA.-Amino Acids.
作者:Masami KAWASE、Hiroshi MIYAMAE、Teruo KURIHARA
DOI:10.1248/cpb.46.749
日期:——
The reactions of N-acyl-N-benzyl-α-amino acids (1) or N-acylprolines (5) with trifluoroacetic anhydride in the presence of pyridine afford 5-trifluoromethyloxazoles (2 or 7) in good yields. The reaction could proceed through the transient formation of mesoionic 1, 3-oxazolium-5-olates, followed by oxazolium salts.
bicyclo[1.1.0]butanes. The mild photoredox conditions, which make use of a readily available and bench stable phenyl sulfonyl bicyclo[1.1.0]butane, proved to be amenable to a diverse range of α-amino and α-oxy carboxylic acids, providing a concise route to 1,3-disubstituted cyclobutanes. Furthermore, kinetic studies and DFT calculations unveiled mechanistic details on bicyclo[1.1.0]butanereactivity relative