Tandem 1,3-dipolar cycloadditions of münchnones. Syntheses and molecular structures of 10-azatetracyclo[6.3.0.04,11.05,9]undecanes and azahomopentaprismane
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.
Direct, Palladium-Catalyzed, Multicomponent Synthesis of β-Lactams from Imines, Acid Chloride, and Carbon Monoxide
作者:Rajiv Dhawan、Rania D. Dghaym、Daniel J. St. Cyr、Bruce A. Arndtsen
DOI:10.1021/ol061308j
日期:2006.8.1
A new palladium-catalyzed synthesis of 3-amido-substituted beta-lactams is reported. This process involves the one-pot coupling of four components, imines, carbonmonoxide, and acidchloride, providing a flexible route to construct this class of heterocycle. The generation of beta-lactams with two different imines can also be accomplished, providing a method to assemble these products with independent
Convenient Synthesis of .ALPHA.-Trifluoromethylated Acyloins from .ALPHA.-Hydroxy or .ALPHA.-Amino Acids.
作者:Masami KAWASE、Setsuo SAITO、Teruo KURIHARA
DOI:10.1248/cpb.48.1338
日期:——
acyloins (2 and 6) have been prepared from alpha-hydroxy acids (1), N-acylprolines (5) or N-acyl-N-alkyl alpha-amino acids (8) by novel transformation reactions with trifluoroacetic anhydride (TFAA) in the presence of pyridine. The former reaction of 1 could proceed through mesoionic 1,3-dioxolium-4-olates, whereas the latter two reactions of alpha-amino acids (5 and 8) could involve mesoionic 1,3-oxazolium-5-olates
New Syntheses of Pyrrolo[3,4-<i>b</i>]indoles, Benzo[<i>b</i>]furo[2,3-<i>c</i>]pyrroles, and Benzo[<i>b</i>]thieno[2,3-<i>c</i>]pyrroles. Utilizing the Reaction of Münchnones (1,3-Oxazolium-5-olates) with Nitroheterocycles
作者:Gordon W. Gribble、Erin T. Pelkey、Frank L. Switzer
DOI:10.1055/s-1998-1887
日期:1998.10
1,3-Dipolar cycloaddition of münchnones (mesoionic 1,3-oxazolium-5-olates) 3 and 4 with 2- and 3-nitroindoles, 2-nitrobenzo[b]furan, and 3-nitrobenzo[b]thiophene affords the corresponding pyrrolo[3,4-b]indoles, benzo[b]furo[2,3-c]pyrroles, and benzo[b]thieno[2,3-c]pyrroles, respectively, in one operation in good to excellent yields.
Palladium-Catalyzed Stille-Type Coupling of <i>N</i>-Acyl Iminium Ions with Distannanes: A Multicomponent Synthesis of α-Amidostannanes
作者:Boran Xu、Bruce A. Arndtsen
DOI:10.1021/cs401164z
日期:2014.3.7
The palladium-catalyzed three-component coupling of imines, acid chlorides, and hexabutyldistannane is described. This results in the synthesis of various α-amidostannanes in good yields, without the use of strong nucleophilic organometallic reagents. The reaction is believed to proceed via a Stille-type cross coupling of an in situ-generated N-acyl iminium salt with Bu3SnSnBu3 and reaches completion