5663-67-2Relevant academic research and scientific papers
One-Pot Generation of Benzynes from Phenols: Formation of Primary Anilines by the Deoxyamination of Phenols
Akai, Shuji,Ikawa, Takashi,Masuda, Shigeaki
, (2020/03/23)
Benzynes were selectively generated in situ from phenols and trapped regioselectively with potassium hexamethyldisilazide to form primary anilines following acidic workup. The direct conversion of a phenolic hydroxyl group into a free amino group is a useful method for the preparation of primary aryl amines that are hard to synthesize by using coupling reactions involving phenol derivatives with ammonia. Whereas reactions of ortho- and meta-substituted phenols produced meta-substituted anilines exclusively, those of para-substituted phenols provided ortho-silylanilines.
The studies on chemoselective promiscuous activity of hydrolases on acylals transformations
Koszelewski, Dominik,Ostaszewski, Ryszard
, (2019/02/27)
Chemoselective, mild and convenient protocol for the hydrolysis of the synthetically relevant acylals via promiscuous enzyme-catalyzed hydrolysis has been developed. It has been shown that promiscuous activity of the used hydrolases dominates their native activity related with carboxylic esters hydrolysis. The main advantage of the present methodology is that it can be conducted under neutral conditions at room temperature. Moreover, complete deprotection of acylals takes place within 10–20 min. Developed protocol can be used with compounds having a variety of hydrolytic labile groups since the cleavage is proceeded under neutral conditions and occurs exclusively on acylal moiety. Further this protocol was extended by the tandem Passerini multicomponent reaction leading to the α-acetoxy amides using acylals as the surrogates of the carbonyl components to P-MCR.
Synthesis method of 5-(2-bromoacetyl)-2-hydroxybenzaldehyde
-
Paragraph 0017, (2019/06/12)
The invention discloses a synthesis method of 5-(2-bromoacetyl)-2-hydroxybenzaldehyde, and belongs to the field of medicine synthesis. According to the method, the acylation reaction is conducted withsalicylaldehyde as the raw material to obtain 2-(acetoxyl)-benzaldehyde, then the rearrangement reaction is conducted, and finally the bromination reaction is conducted to obtain 5-(2-bromoacetyl)-2-hydroxybenzaldehyde. The preparing method has the advantages of being high in product purity and high in yield.
Generation of Phosphoranyl Radicals via Photoredox Catalysis Enables Voltage-Independent Activation of Strong C-O Bonds
Stache, Erin E.,Ertel, Alyssa B.,Rovis, Tomislav,Doyle, Abigail G.
, p. 11134 - 11139 (2018/11/21)
Despite the prevalence of alcohols and carboxylic acids as functional groups in organic molecules and the potential to serve as radical precursors, C-O bonds remain difficult to activate. We report a synthetic strategy for direct access to both alkyl and acyl radicals from these ubiquitous functional groups via photoredox catalysis. This method exploits the unique reactivity of phosphoranyl radicals, generated from a polar/SET crossover between a phosphine radical cation and an oxygen-centered nucleophile. We show the desired reactivity in the reduction of benzylic alcohols to the corresponding benzyl radicals with terminal H atom trapping to afford the deoxygenated products. Using the same method, we demonstrate access to synthetically versatile acyl radicals, which enables the reduction of aromatic and aliphatic carboxylic acids to the corresponding aldehydes with exceptional chemoselectivity. This protocol also transforms carboxylic acids to heterocycles and cyclic ketones via intramolecular acyl radical cyclizations to forge C-O, C-N, and C-C bonds in a single step.
Selective reduction of carboxylic acids to aldehydes with hydrosilane: Via photoredox catalysis
Zhang, Muliang,Li, Nan,Tao, Xingyu,Ruzi, Rehanguli,Yu, Shouyun,Zhu, Chengjian
supporting information, p. 10228 - 10231 (2017/09/22)
The direct reduction of carboxylic acids to aldehydes with hydrosilane was achieved through visible light photoredox catalysis. The combination of both single electron transfer and hydrogen atom transfer steps offers a novel and convenient approach to selective reduction of carboxylic acids to aldehydes. The method also features mild conditions, high yields, broad substrate scope, and good functional group tolerance, such as alkyne, ester, ketone, amide and amine groups.
(Z)-selective Takai olefination of salicylaldehydes
Geddis, Stephen M.,Hagerman, Caroline E.,Galloway, Warren R. J. D.,Sore, Hannah F.,Goodman, Jonathan M.,Spring, David R.
supporting information, p. 323 - 328 (2017/03/14)
The Takai olefination (or Takai reaction) is a method for the conversion of aldehydes to vinyl iodides, and has seen widespread implementation in organic synthesis. The reaction is usually noted for its high (E)-selectivity; however, herein we report the
Green procedures for the chemoselective synthesis of acylals and their cleavage promoted by recoverable sulfonic acid based nanoporous carbon (CMK-5-SO3H)
Zareyee, Daryoush,Mirzajanzadeh, Ehsan,Khalilzadeh, Mohammad Ali
, p. 1229 - 1234 (2015/10/06)
A selective synthesis of gem-diacetates from the reaction of aldehydes and acetic anhydride in the presence of recyclable nanoporous solid sulfonic acid (CMK-5-SO3H) under solvent-free reaction conditions is reported. The catalyst was also found to be highly active for deprotection of resulting acylals in water. [Figure not available: see fulltext.]
Silver Tetrafluoroborate-Catalyzed Oxa-Diels-Alder Reaction between Electrically Neutral Dienes and Aldehydes
Zou, Xiaodong,Yang, Lizheng,Liu, Xiangli,Sun, Hao,Lu, Hongjian
supporting information, p. 3040 - 3046 (2015/11/03)
Chemoselective oxa-Diels-Alder reactions between electrically neutral 1,3-dienes and various aldehydes were achieved using the commercially available silver tetrafluoroborate (AgBF4) as catalyst. This catalytic process has high functional group tolerance. Heteroatoms at the β-position of the aryl aldehydes can greatly promote the reactivity of the substrates even with heterocyclic aldehydes that were previously believed to be unreactive for the oxa-Diels-Alder reaction. In addition, acroleins with β-heteroatom substitution are also good substrates. High chemoselectivity and regioselectivity were achieved at room temperature for the oxa-Diels-Alder reaction between acroleins and stoichiometric simple 1,3-dienes.
Effective synthesis of kynurenine-containing peptides via on-resin ozonolysis of tryptophan residues: Synthesis of cyclomontanin B
Wong, Clarence T. T.,Lam, Hiu Yung,Li, Xuechen
supporting information, p. 7616 - 7620 (2013/11/06)
The preparation of Kyn-containing peptides is difficult, owing to the low reactivity of Kyn in the coupling reaction. In this report, Kyn-containing peptides were efficiently obtained via on-resin ozonolysis of the corresponding Trp-containing peptide. In
Synthesis of constrained head-to-tail cyclic tetrapeptides by an imine-induced ring-closing/contraction strategy
Wong, Clarence T. T.,Lam, Hiu Yung,Song, Tao,Chen, Guanhua,Li, Xuechen
supporting information, p. 10212 - 10215 (2013/10/21)
Making heads or tails of it: A strategy involving a head-to-tail imine-captured ring closure followed by ring contraction was used to synthesize otherwise difficult cyclic tetrapeptides. Compared with the direct lactamization process, the estimated activa
