The three-component Petasis borono-Mannich reaction starting with easily accessible N-protected α-amino aldehydes produces efficiently and diastereoselectively 1,2-trans-diamines with an enantiomeric excess of up to 98%.
carboxylic acids with organoborons has been realized using either mono-protected aminoacid (MPAA) ligands or mono-protected aminoethyl amine (MPAAM) ligands. A diverse range of aryl- and vinyl-boron reagents can be used as coupling partners to provide chiral carboxylic acids. This reaction provides an alternative approach to the enantioselective synthesis of cyclopropanecarboxylic acids and cyclobutanecarboxylic
Palladium(II)-Catalyzed Enantioselective C(sp<sup>3</sup>)–H Activation Using a Chiral Hydroxamic Acid Ligand
作者:Kai-Jiong Xiao、David W. Lin、Motofumi Miura、Ru-Yi Zhu、Wei Gong、Masayuki Wasa、Jin-Quan Yu
DOI:10.1021/ja504196j
日期:2014.6.4
An enantioselective method for Pd(II)-catalyzed cross-coupling of methylene β-C(sp3)–H bonds in cyclobutanecarboxylic acid derivatives with arylboron reagents is described. High yields and enantioselectivities were achieved through the development of chiral mono-N-protected α-amino-O-methylhydroxamic acid (MPAHA) ligands, which form a chiral complex with the Pd(II) center. This reaction provides an
Ligand-Enabled <i>meta</i>-Selective C–H Arylation of Nosyl-Protected Phenethylamines, Benzylamines, and 2-Aryl Anilines
作者:Qiuping Ding、Shengqing Ye、Guolin Cheng、Peng Wang、Marcus E. Farmer、Jin-Quan Yu
DOI:10.1021/jacs.6b11097
日期:2017.1.11
meta-selective C-H arylation of nosyl-protected phenethylamines and benzylamines is disclosed using a combination of norbornene and pyridine-based ligands. Subjecting nosyl protected 2-aryl anilines to this protocol led to meta-C-H arylation at the remote aryl ring. A diverse range of aryl iodides are tolerated in this reaction, along with select heteroaryl iodides. Select aryl bromides bearing ortho-coordinating
N-Alkylation of N-arylsulfonyl-α-amino acid methyl esters by trialkyloxonium tetrafluoroborates
作者:Rosaria De Marco、Maria Luisa Di Gioia、Angelo Liguori、Francesca Perri、Carlo Siciliano、Mariagiovanna Spinella
DOI:10.1016/j.tet.2011.10.042
日期:2011.12
tetrafluoroborate is the reagent of choice for the direct and quantitative N-methylation. Further we extend our evaluation to the use of triethyloxonium tetrafluoroborate. This reagent shows to be very efficient in order to prepare N-ethyl derivatives of N-arylsulfonyl-α-amino acid methyl esters. An experimental protocol similar to that used for N-methylation with trimethyloxonium tetrafluoroborate is applied