(cis-β-N-RO-amide-VBXs) from O-alkyl hydroxamic acids in the presence of an ethynyl benziodoxolone–acetonitrile complex (EBX–MeCN) is reported herein. The reaction was performed under mild conditions including an aqueous solvent, a mild base, and room temperature. The reaction tolerated various O-alkyl hydroxamic acids derived from carboxylicacids, such as amino acids, pharmaceuticals, and natural products
本文报道了在乙炔基苯并恶唑啉酮-乙腈络合物(EBX-MeCN)存在下,由O-烷基异羟肟酸立体合成顺式-β- N-烷氧基酰胺乙烯基苯并恶唑烷(顺式-β - N -RO-酰胺-VBXs)。反应在温和的条件下进行,所述条件包括水性溶剂,温和的碱和室温。该反应容许各种衍生自羧酸的O-烷基异羟肟酸,例如氨基酸,药物和天然产物。还使用氧化氘作为氘源合成了乙烯基双氘化的顺式-β - N -MeO-酰胺-VBXs。缬氨酸衍生的顺式将-β - N - MeO-酰胺-VBX立体定向衍生为异羟肟酸衍生的顺式-酰胺,而不会失去立体选择性或降低氘/氢比。
Palladium(<scp>ii</scp>)-catalyzed asymmetric C–H carbonylation to diverse isoquinoline derivatives bearing all-carbon quaternary stereocenters
作者:Yan Li、Xiu-Fen Cheng、Fan Fei、Tian-Rui Wu、Kang-Jie Bian、Xin Zhou、Xi-Sheng Wang
DOI:10.1039/d0cc05219a
日期:——
Enantioselective synthesis of tetrahydroisoquinolines bearing an all-carbon quaternary stereogenic center, was achieved via asymmetric C–H activation with high enantioselectivities (up to 93% ee). Fair substrate tolerance was indicated throughout the scope investigation and no evident loss of enantioselectivity was exhibited in late-stage derivatization. This study provides incentives for the construction
Direct synthesis of hydroxamates from carboxylic acids using 2-mercaptopyridone-1-oxide-based thiouronium salts
作者:Miguel A Bailén、Rafael Chinchilla、David J Dodsworth、Carmen Nájera
DOI:10.1016/s0040-4039(01)00923-6
日期:2001.7
Tetrafluoroborate and hexafluorophosphate thiouronium salts derived from 2-mercaptopyridone-1-oxide and tetramethylurea (TOTT and HOTT) or N,N ' -dimethylpropyleneurea (TODT and HODT) convert carboxylic acids to Weinreb amides and N-methoxy or N-benzoxyamides in high yields by reaction with N,O-dimethylhydroxylamine and O-methyl- or O-benzyl-hydroxylamine hydroxylamine hydrochlorides. respectively. in the presence of triethylamine or DIEA. (C) 2001 Elsevier Science Lid. All rights reserved.