81616-14-0Relevant articles and documents
Photochemical regioselective C(sp3)-H amination of amides using N-haloimides
Pan, Lei,Elmasry, Joseph,Osccorima, Tomas,Cooke, Maria Victoria,Laulhé, Sébastien
supporting information, p. 3389 - 3393 (2021/05/07)
A metal-free regioselective C(sp3)-H amination of amides using N-haloimides in the presence of lithium tert-butoxide and visible light is presented herein. This photoexcited approach is straightforward, and it aminates a wide variety of amides under mild conditions without the use of photocatalysts, external radical initiators, or oxidants. A halogen-bonded intermediate between the tert-butoxide base and the N-haloimide is proposed to be responsible for the increased photoreactivity. Calculations show that the formation of this electron donor-acceptor complex presents an exergonic energy profile.
Sustainable Route Toward N-Boc Amines: AuCl3/CuI-Catalyzed N-tert-butyloxycarbonylation of Amines at Room Temperature
Cao, Yanwei,He, Lin,Huang, Yang
, (2021/12/22)
N-tert-butoxycarbonyl (N-Boc) amines are useful intermediates in synthetic/medicinal chemistry. Traditionally, they are prepared via an indirect phosgene route with poor atom economy. Herein, a step- and atom-economic synthesis of N-Boc amines from amines, t-butanol, and CO was reported at room temperature. Notably, this N-tert-butyloxycarbonylation procedure utilized ready-made substrates, commercially available AuCl3/CuI as catalysts, and O2 from air as the sole oxidant. This catalytic system provided unique selectivity for N-Boc amines in good yields. More significantly, gram-scale preparation of medicinally important N-Boc amine intermediates was successfully implement, which demonstrated a potential application prospect in industrial syntheses. Furthermore, this approach also showed good compatibility with tertiary and other useful alcohols. Investigations of the mechanisms revealed that gold catalyzed the reaction and copper acted as electron transfer mediator in the catalytic cycle.
Synthesis of Amide Enol Carbamates and Carbonates through Cu(OTf)2-Catalyzed Reactions of Ynamides with t-Butyl Carbamates/Carbonates
Han, Pan,Mao, Zhuo-Ya,Li, Ming,Si, Chang-Mei,Wei, Bang-Guo,Lin, Guo-Qiang
, p. 4740 - 4752 (2020/04/30)
A highly regioselective approach to access amide enol carbamates and carbonates 5a-5c′, 7a-7h, and 9 was developed through Cu(OTf)2-catalyzed reactions of ynamides 4 with t-butyl carbamates 2 and 8 and t-butyl carbonates 6. Moreover, this strategy was successfully applied to generate amide enol carbamates 11a-11s and 14a-14f from imides 10 and 13 with ynamides through an N-Boc cleavage-addition ring-opening process. A range of substituents was amenable to this transformation, and the desired amide enol carbamates and carbonates were obtained in moderate to good yields.
Hydrosilane-Promoted Facile Deprotection of tert-Butyl Groups in Esters, Ethers, Carbonates, and Carbamates
Ikeda, Takuya,Zhang, Zhenzhong,Motoyama, Yukihiro
supporting information, p. 673 - 677 (2019/01/04)
Combination of PdCl2 with 1,1,3,3-tetramethyldisiloxane in the presence of activated carbon was found to be an effective catalyst system for the cleavage reaction of C?O bond of O?t-Bu moieties. The present catalytic reaction offers a practical method for the deprotection of tert-butyl esters, tert-butyl ethers, O-Boc, and N-Boc derivatives under mild conditions. The addition of activated carbon in the reaction mixture was proved to be crucial for not only sustaining the catalytic activity but also trapping the palladium species after the reaction. (Figure presented.).
Highly chemoselective, sterically sensitive NHC-catalysed amine acylation with pyridil
Maguire, Amy C.,Kumar, Vikas,Connon, Stephen J.
supporting information, p. 13526 - 13529 (2019/11/14)
A new strategy for the protection of amines has been developed involving reaction with pyridil under the influence of N-heterocyclic carbene catalysis. The methodology is capable of distinguishing between two amines characterised by small differences in steric bulk and the resulting pyridoyl amides can be cleaved without requiring either strongly acidic or basic hydrolysis.
Selective Monomethylation of Amines with Methanol as the C1 Source
Choi, Geunho,Hong, Soon Hyeok
supporting information, p. 6166 - 6170 (2018/04/30)
The N-monomethyl functionality is a common motif in a variety of synthetic and natural compounds. However, facile access to such compounds remains a fundamental challenge in organic synthesis owing to selectivity issues caused by overmethylation. To address this issue, we have developed a method for the selective, catalytic monomethylation of various structurally and functionally diverse amines, including typically problematic primary aliphatic amines, using methanol as the methylating agent, which is a sustainable chemical feedstock. Kinetic control of the aliphatic amine monomethylation was achieved by using a readily available ruthenium catalyst at an adequate temperature under hydrogen pressure. Various substrates including bio-related molecules and pharmaceuticals were selectively monomethylated, demonstrating the general utility of the developed method.
Amidation of unactivated ester derivatives mediated by trifluoroethanol
McPherson, Christopher G.,Caldwell, Nicola,Jamieson, Craig,Simpson, Iain,Watson, Allan J. B.
supporting information, p. 3507 - 3518 (2017/04/26)
A catalytic amidation protocol mediated by 2,2,2-trifluoroethanol has been developed, facilitating the condensation of unactivated esters and amines, furnishing both secondary and tertiary amides. The complete scope and limitations of the method are described, along with modified conditions for challenging substrates such as acyclic secondary amines and chiral esters with retention of chiral integrity.
Palladium-Catalyzed C(sp3)-H Arylation of N-Boc Benzylalkylamines via a Deprotonative Cross-Coupling Process
Hussain, Nusrah,Kim, Byeong-Seon,Walsh, Patrick J.
supporting information, p. 11010 - 11013 (2015/11/10)
Diarylmethylamines are key intermediates and products in the pharmaceutical industry. Herein we disclose a novel method toward the synthesis of these important compounds via C-H functionalization. Presented is a reversible deprotonation of N-Boc benzylalkylamines at the benzylic C-H with in situ arylation by a NiXantPhos-based palladium catalyst (50-93 % yield, 29 examples). The method is also successful with N-Boc-tetrahydroisoquinolines. The advantages of this method are it avoids strong bases, low temperatures, and the need to transmetallate to main group metals for the coupling. Skipping steps! Diarylmethylamines are key intermediates and products in the pharmaceutical industry. A novel method toward the synthesis of these important compounds via C-H functionalization is reported. A reversible deprotonation of N-Boc benzylalkylamines at the benzylic C-H is coupled with in situ arylation with a (NiXantPhos)Pd-based catalyst (50-93 % yield, 29 examples). The advantages of this method are that it avoids strong bases, low temperatures, and the need to transmetallate to main group metals for the coupling.
Ligand-controlled α- And β-arylation of acyclic N-boc amines
Millet, Anthony,Dailler, David,Larini, Paolo,Baudoin, Olivier
, p. 2678 - 2682 (2014/03/21)
The palladium-catalyzed ligand-controlled arylation of α-zincated acyclic amines, obtained by directed α-lithiation and transmetalation, is described. Whereas PtBu3 gave rise to α-arylated Boc-protected amines, more flexible N-phenylazole-based phosphine ligands induced major β-arylation through migrative cross-coupling. All manner of control: The arylation of α-zincated acyclic Boc-protected amines was selectively performed at the α- or β-position in a ligand-controlled manner. α-Arylation occurs by direct reductive elimination of the α-palladated intermediate whereas β-arylation involves palladium migration along the alkyl chain. Boc=tert-butoxycarbonyl.
Smooth isoindolinone formation from isopropyl carbamates via bischler-napieralski-type cyclization
Adachi, Satoshi,Onozuka, Masao,Yoshida, Yuko,Ide, Mitsuaki,Saikawa, Yoko,Nakata, Masaya
supporting information, p. 358 - 361 (2014/04/03)
Isopropyl carbamates derived from benzylamines provide isoindolinones by treatment with phosphorus pentoxide at room temperature. Utility of this Bischler-Napieralski-type cyclization and a new mechanism involving a carbamoyl cation for rationalization of this smooth conversion are discussed.
