1-AMINO-1-ARYL- AND 1-AMINO-1-HETEROARYL-METHANEPHOSPHONIC ACIDS AND THEIRN-BENZHYDRYL–PROTECTED DIETHYL ESTERS: PREPARATION AND CHARACTERIZATION
摘要:
N-Benzhydryl-protected diethyl esters of 1-amino-1-aryl- (phenyl, cumyl, p-dimethylaminophenyl, piperonyl, 1'-naphthyl, 9'-anthryl, T-pyrenyl) and 1-ainino-1-heteroaryl- (furyl, 2'-thienyl, X-thienyl, 2'-pyrrolyl)-methanephosphonic acids, prepared by the addition of diethyl phosphite to the corresponding benzhydryl imines, have been isolated, purified, and characterized. The presence of chiral alpha-carbon and prochiral phosphorus in these esters gives rise to complicated features in their NMR spectra, which are discussed. Hydrolysis of the crude 1-aryl compounds in situ gave modest yields of the corresponding aminophosphonic acids (except for 1'-pyrenyl). Of the 1-heteroaryl derivatives, only the 2'-thienyl compound gave the expected aminophosphonic acid; in other cases, alternative modes of decomposition may occur under hydrolytic conditions. NMR and mass spectral data are given for all products.
Vaulted Biaryls in Catalysis: A Structure-Activity Relationship Guided Tour of the Immanent Domain of the VANOL Ligand
作者:Yong Guan、Zhensheng Ding、William D. Wulff
DOI:10.1002/chem.201302451
日期:2013.11.11
anion (boroxinate) that is assembled in situ from three equivalents of B(OPh)3 and one of the VANOLligand by a molecule of substrate. The substrates are bound to the boroxinate by H bonds to oxygen atoms O1–O3. The effects of introducing substituents at each position of the naphthalene core of the VANOLligand are systematically investigated in an aziridination reaction. Substituents in the 4,4′‐ and
A practical procedure for catalytic asymmetric synthesis of opticallyactive arylglycine derivatives viaopticallyactive α-aminonitriles has been developed. The N-benzhydryl α-arylaminonitrile intermediates were prepared in excellent yield (89–99%) and enantiomeric purity (96 to >98% ee) by enantioselective cyanation of aldimines with TMSCN/iPrOH in the presence of 2.5 mol % of an easily prepared
Microwave-assisted synthesis of α-aminophosphonates with sterically demanding α-aryl substituents
作者:Harry R. Hudson、Ádám Tajti、Erika Bálint、Mátyás Czugler、Konstantin Karaghiosoff、György Keglevich
DOI:10.1080/00397911.2019.1679186
日期:2020.5.18
Abstract A series of N-benzhydryl protected α-aminophosphonates with α-phenyl, α-(1-naphtyl), α-(9-anthryl) or α-(1-pyrenyl) substituents was synthesized by the Kabachnik–Fields condensation of diphenylmethylamine (benzhydrylamine), the corresponding aryl aldehyde and a dialkyl phosphite under MW irradiation. X-ray studies performed at low temperatures for a few of these α-aminophosphonates confirmed
Catalytic Asymmetric Aziridination with Borate Catalysts Derived from VANOL and VAPOL Ligands: Scope and Mechanistic Studies
作者:Yu Zhang、Aman Desai、Zhenjie Lu、Gang Hu、Zhensheng Ding、William D. Wulff
DOI:10.1002/chem.200701558
日期:2008.4.18
An extended study of the scope and mechanism of the catalyticasymmetricaziridination of imines with ethyl diazoacetate mediated by catalysts preparedfrom the VANOL and VAPOL ligands and triphenylborate is described. Nonlinear studies with scalemic VANOL and VAPOL reveal an essentially linear relationship between the optical purity of the ligand and the product suggesting that the catalyst incorporates
Extremely short H···H distances and intermolecular hydrogen-bonding patterns of dialkyl α-aryl-α-(diphenylmethylamino)methanephosphonates
作者:Harry R. Hudson、Mátyás Czugler、Rosalind J. Lee、Thomas M. Woodroffe
DOI:10.1080/10426507.2015.1091833
日期:2016.3.3
types of hydrogenbonding, leading to the formation of (a) dimers containing two molecules of the same stereochemistry (SS or RR) in one case, (b) centrosymmetric dimers containing two enantiomeric molecules (RS) (both involving P=O···H–N interactions) in two crystals, and (c) in the anthryl derivative, a short intramolecular C–H···O=P contact distance but no involvement of the amino N–H. The anthryl