27593-61-9Relevant articles and documents
Asymmetric allylboration of acyl imines catalyzed by chiral diols
Lou, Sha,Moquist, Philip N.,Schaus, Scott E.
, p. 15398 - 15404 (2008/09/18)
Chiral BINOL-derived diols catalyze the enantioselective asymmetric allylboration of acyl imines. The reaction requires 15 mol % (S)-3,3′-Ph2-BINOL as the catalyst and allyldiisopropoxyborane as the nucleophile. The reaction products are obtained in good yields (75-94%) and high enantiomeric ratios (95:5-99.5:0.5) for aromatic and aliphatic imines. High diastereoselectivities (diastereomeric ratio > 98:2) and enantioselectivities (enantiomeric ratio > 98:2) are obtained in the reactions of acyl imines with crotyldiisopropoxyboranes. This asymmetric transformation is directly applied to the synthesis of Maraviroc, the selective CCR5 antagonist with potent activity against HIV-1 infection. Mechanistic investigations of the allylboration reaction including IR, NMR, and mass spectrometry studies indicate that acyclic boronates are activated by chiral diols via exchange of one of the boronate alkoxy groups with activation of the acyl imine via hydrogen bonding.
Solid-phase synthesis of 4-methylene pyrrolidines and allylic amines using palladium-activated allylic linkers
Brown, Richard C.D.,Fisher, Martyn L.,Brown, Lynda J.
, p. 2699 - 2709 (2007/10/03)
The solid-phase synthesis of 4-methylene pyrrolidines and allylic amines has been achieved using palladium-catalysed nucleophilic cleavage of allylic linkages. Six pyrrolidines were synthesised in five steps from a carboxyethyl resin 20, where the key transformations included a Lewis-acid promoted imino-Sakurai type reaction and reductive alkylation prior to the final palladium-catalysed cyclisation cleavage of the allylic carboxylate linkage. Allylic carboxylate resin 22 was also shown to undergo "traceless" cleavage using various hydride sources in the presence of catalytic palladium. A more robust allylic ether linkage was also investigated. Starting from a phenol resin 36, a number of 3-aryl-allylaniines were prepared using a palladium-catalysed nucleophilic cleavage reaction.
Scope and limitations in sulfur ylide mediated catalytic asymmetric aziridination of imines: Use of phenyldiazomethane, diazoesters and diazoacetamides
Aggarwal,Ferrara,O'Brien,Thompson,Jones,Fieldhouse
, p. 1635 - 1643 (2007/10/03)
Imine aziridination using diazo-compounds and catalytic quantities of metal salts and sulfides has been investigated. A range of imines derived from benzaldehyde bearing electron-withdrawing groups (N-Ts,N-SO2CH2CH2SiMesu
N-alkyloxycarbonyl-3-aryloxaziridines: Their preparation, structure, and utilization as electrophilic amination reagents
Vidal, Joelle,Damestoy, Stephanie,Guy, Laure,Hannachi, Jean-Christophe,Aubry, Andre,Collet, Andre
, p. 1691 - 1709 (2007/10/03)
This paper reports the synthesis of a series of N-protected oxaziridines (N-Moc, Boc, Z or Fmoc) and discusses their ability to deliver their N-alkoxycarbonyl fragment to amines, enolates, sulfur, and phosphorus nucleophiles (electrophilic amination). These oxaziridines are prepared by oxidation of the corresponding imines with oxone or anhydrous MCPBA lithium salt as the source of oxygen. They transfer their N-protected fragment to primary and secondary amines to give protected hydrazines in fair to excelent yield. The nitrogen transfer to free amino acids (in form of their R4N+ salts) is particularly fast, even at low temperature, providing L (or D) N-protected α-hydrazino acids. Enolates are C-aminated to give N-protected α-amino ketones, esters, or amides in modest yield, due to a side aldol reaction of the unreacted enolate with the released benzaldehyde. With tertiary amines (Et3N), sulfides (PhSMe), and phosphines (Ph3P), amination and oxidation proceed in a parallel way; the amount of amination product increases when the temperature is lowered (kinetic control). Some of the factors that can orient the oxaziridine reactivity towards amination or oxidation of nucleophiles are considered.
Electrophilic Amination: Preparation and Use of N-Boc-3-(4-cyanophenyl)oxaziridine, a New Reagent That Transfers a N-Boc Group to N- and C-Nucleophiles
Vidal, Joelle,Guy, Laure,Sterin, Sebastien,Collet, Andre
, p. 4791 - 4793 (2007/10/02)
We describe the preparation of the title compound 2b via aza-Wittig reaction of N-Boc-triphenyliminophosphorane (6) with 4-cyanobenzaldehyde followed by Oxone oxidation of the resulting imine 5b.Oxaziridine 2b is a stable, crystalline solid, which transfers under mild conditions its N-Boc fragment to primary and secondary amines (to give Nβ-Boc-hydrazines) and enolates (to give N-Boc-amino drivatives).
N-Amination Using N-Methoxycarbonyl-3-phenyloxaziridine. Direct Access to Chiral Nβ-Protected α-Hydrazinoacids and Carbazates
Vidal, Joelle,Drouin, Jacques,Collet, Andre
, p. 435 - 437 (2007/10/02)
Primary and secondary amines =NH, including α-aminoacids, can be converted under mild conditions to the corresponding carbazates =N-NH-CO2Me, on reaction with N-methoxycarbonyl-3-phenyloxaziridine 1.
