7529-63-7Relevant academic research and scientific papers
Cleavage∕cross-coupling strategy for converting β-O-4 linkage lignin model compounds into high valued benzyl amines via dual C–O bond cleavage
Jia, Le,Li, Chao-Jun,Zeng, Huiying
supporting information, (2021/10/29)
Lignin is the most recalcitrant of the three components of lignocellulosic biomass. The strength and stability of the linkages have long been a great challenge for the degradation and valorization of lignin biomass to obtain bio-fuels and commercial chemicals. Up to now, the selective cleavage of C–O linkages of lignin to afford chemicals contains only C, H and O atoms. Our group has developed a cleavage/cross-coupling strategy for converting 4-O-5 linkage lignin model compounds into high value-added compounds. Herein, we present a palladium-catalyzed cleavage/cross-coupling of the β-O-4 lignin model compounds with amines via dual C–O bond cleavage for the preparation of benzyl amine compounds and phenols.
Sustainable Production of Benzylamines from Lignin
Guo, Tenglong,Kühn, Fritz E.,Li, Changzhi,Liu, Yuxuan,Wang, Chao,Xiao, Jianliang,Zhang, Bo,Zhang, Tao,Zhao, Zongbao K.
supporting information, p. 20666 - 20671 (2021/08/25)
Catalytic conversion of lignin into heteroatom functionalized chemicals is of great importance to bring the biorefinery concept into reality. Herein, a new strategy was designed for direct transformation of lignin β-O-4 model compounds into benzylamines and phenols in moderate to excellent yields in the presence of organic amines. The transformation involves dehydrogenation of Cα?OH, hydrogenolysis of the Cβ?O bond and reductive amination in the presence of Pd/C catalyst. Experimental data suggest that the dehydrogenation reaction proceeds over the other two reactions and secondary amines serve as both reducing agents and amine sources in the transformation. Moreover, the concept of “lignin to benzylamines” was demonstrated by a two-step process. This work represents a first example of synthesis of benzylamines from lignin, thus providing a new opportunity for the sustainable synthesis of benzylamines from renewable biomass, and expanding the products pool of biomass conversion to meet future biorefinery demands.
Copper-Catalyzed Asymmetric Hydroamination of Styrenes with pivZPhos as Ligand
Chen, Chengsheng,Wu, Ling,Wang, Yuwen,Wu, Linglin,Zhang, Yongda
supporting information, p. 3415 - 3419 (2020/09/15)
A copper-catalyzed hydroamination of styrenes using pivZPhos as ligand is reported. Enantioselectivities up to 94% are achieved under optimized conditions with aryl and heteroaryl styrenes. A variety of electrophilic O -benzoylhydroxylamines are well tolerated.
Copper-Catalyzed Carbonylative Hydroamidation of Styrenes to Branched Amides
Yuan, Yang,Wu, Fu-Peng,Schünemann, Claas,Holz, Jens,Kamer, Paul C. J.,Wu, Xiao-Feng
supporting information, p. 22441 - 22445 (2020/10/12)
Amides are one of the most ubiquitous functional groups in synthetic and medicinal chemistry. Novel and rapid synthesis of amides remains in high demand. In this communication, a general and efficient procedure for branch-selective hydroamidation of vinylarenes with hydroxyamine derivatives enabled by copper catalysis has been developed for the first time. The reaction proceeds under mild conditions and tolerates a broad range of functional groups. Applying a chiral phosphine ligand, an enantioselective variant of this transformation was achieved, affording a variety of chiral α-amides with excellent enantioselectivities (up to 99 % ee) and high yields.
Formal Synthesis of (–)-Perhydrohistrionicotoxin Using a Thorpe-Ziegler Cyclization Approach. Synthesis of Functionalized Aza-Spirocycles
Vu, Van Ha,Bouvry, Christelle,Roisnel, Thierry,Golhen, Stéphane,Hurvois, Jean-Pierre
, p. 1215 - 1224 (2019/01/04)
The formal synthesis of (–)-PHTX is described. Our approach was based on the anodic cyanation of (S)-1-(1-phenylethyl)-piperidine (–)-1 to afford α-aminonitrile 2 in 85 % yield in a 53:47 dr. The presence of the α-phenylethyl group as the chiral auxiliary
Iron-Catalysed Reductive Amination of Carbonyl Derivatives with Ω-Amino Fatty Acids to Access Cyclic Amines
Wei, Duo,Netkaew, Chakkrit,Carré, Victor,Darcel, Christophe
, p. 3008 - 3012 (2019/05/15)
An efficient method for the reductive amination of carbonyl derivatives with ω-amino fatty acids catalysed by an iron complex Fe(CO)4(IMes) [IMes=1,3-bis(2,4,6-trimethylphenyl)imidazol-2-ylidene] by means of hydrosilylation was developed. A variety of pyrrolidines, piperidines and azepanes were selectively synthesised in moderate-to-excellent yields (36 examples, 47–97 % isolated yield) with a good functional group tolerance.
Straightforward α-Amino Nitrile Synthesis Through Mo(CO)6-Catalyzed Reductive Functionalization of Carboxamides
Trillo, Paz,Slagbrand, Tove,Adolfsson, Hans
, p. 12347 - 12351 (2018/09/10)
The selective reduction of amides into an intermediate hemiaminal catalyzed by Mo(CO)6 together with the inexpensive and easy to handle TMDS (1,1,3,3-tetramethyldisiloxane) as reducing agent, followed by subsequent trapping of the hemiaminal with a cyanide source, allows for the straightforward synthesis of α-amino nitriles. The methodology presented here, displays high levels of chemoselectivity allowing for the reduction of amides in the presence of functional groups such as ketones, imines, aldehydes, and acids, which affords a simple route for the synthesis of α-amino nitriles with a broad scope of functionalities in high yields. Furthermore, the applicability of this methodology is demonstrated by scale up experiments and by derivatization of the target compounds into synthetically interesting products. The selective cyanation is successfully applied in late stage functionalizations of amide containing drugs and prolinol derivatives.
Unusual 1,1-Hydroboration Route to a Reactive Unsaturated Vicinal Frustrated Phosphane/Borane Lewis Pair
Ueno, Atsushi,Tao, Xin,Daniliuc, Constantin G.,Kehr, Gerald,Erker, Gerhard
supporting information, p. 2665 - 2668 (2018/09/10)
Piers' borane HB(C6F5)2 reacted with the alkyne Mes2P-C≡ ≡C-SiMe3 by a rarely observed 1,1-hydroboration reaction under kinetic control to give the unsaturated vicinal frustrated phosphane/borane Lewis pair 6, featuring both the PMes2 and SiMe3 groups at the same carbon atom C1. Compound 6 is a reactive P/B FLP which splits dihydrogen under mild conditions. Thermolysis at 100 °C converts it to the markedly less reactive P/B FLP regioisomer which bears the -SiMe3 substituent at carbon atom C2 adjacent to the B(C6F5)2 group. Most new compounds were characterized by X-ray diffraction.
FLP-Catalyzed Transfer Hydrogenation of Silyl Enol Ethers
Khan, Imtiaz,Reed-Berendt, Benjamin G.,Melen, Rebecca L.,Morrill, Louis C.
supporting information, p. 12356 - 12359 (2018/09/18)
Herein we report the first catalytic transfer hydrogenation of silyl enol ethers. This metal free approach employs tris(pentafluorophenyl)borane and 2,2,6,6-tetramethylpiperidine (TMP) as a commercially available FLP catalyst system and naturally occurring γ-terpinene as a dihydrogen surrogate. A variety of silyl enol ethers undergo efficient hydrogenation, with the reduced products isolated in excellent yields (29 examples, 82 % average yield).
Selective formation of heterocyclic: Trans -cycloalkenes by alkyne addition to a biphenylene-based phosphane/borane frustrated Lewis pair
Li, Jun,Daniliuc, Constantin G.,Kehr, Gerald,Erker, Gerhard
supporting information, p. 6344 - 6347 (2018/06/22)
The intramolecular 1-PMes2/8-B(C6F5)2 substituted biphenylene frustrated Lewis pair 4 shows some behavior reminiscent of intermolecular FLP systems. It undergoes trans-1,2-addition to a series of 1-alkynes to give the respective heterocyclic eight-membered E-alkenes 8. The P/B FLP 4 also reacts with triplet dioxygen to yield the [P]-O-[B](OC6F5) containing oxygenation product.
