127921-76-0Relevant articles and documents
Hendrickson reagent induced rearrangement of aryl propargyl alcohols to α,β-unsaturated aldehydes
Moussa, Ziad,Aljuhani, Ateyatallah
, p. 845 - 853 (2018/11/06)
The Hendrickson reagent (triphenylphosphonium anhydride trifluoromethanesulfonate), prepared from the reaction of triphenylphosphine oxide (Ph3PO) and triflic anhydride (Tf2O) (2:1 stoichiometry), promotes dehydrations and various coupling reactions. The reagent has been used to transform oximes to nitriles and to prepare esters, amides and many other functional groups through the intermediacy of an alkoxyphosphonium salt. The reagent proved useful in heterocycle synthesis of thiazolines, imidazolines, quinoline precursors, isoquinolines, β-carbolines, phenanthridines, 11H-indolo[3,2-c]quinolines, quinoline-lactones, furoquinolinones, and indolizino[1,2-b]quinolin-9(11H)-ones. Moreover, the reagent has been key to the successful total synthesis of several natural products. Aryl propargyl alcohols with a terminal α-acetylenic group undergo rapid conversion to the corresponding α,β-unsaturated aldehydes at room temperature in dichloromethane in the presence of one equivalent of triphenylphosphonium anhydride trifluoromethanesulfonate. The reaction involved adding freshly distilled Tf2O (1.0 mmol) to a solution of Ph3PO (2.0 mmol) in CH2Cl2 (10 mL) at 0oC under N2 atmosphere. After stirring for 10 min, the propargyl alcohol (1.0 mmol) was added as a CH2Cl2 solution (2 mL), followed by the addition of water and Et3N (2.0 mmol) and further stirring at room temperature for 1h. Subsequent workup with 5% NaHCO3 (20 mL) and purification afforded α,β-unsaturated aldehydes. Eighteen aryl propargyl alcohol substrates with a terminal α-acetylenic group were transformed in good to excellent yields (71-85%) to enals. The methodology proved successful with secondary and tertiary alcohols with stereoselectivity favouring exclusively the E isomer. All the synthesized compounds are known and were characterized (1H,13C, and M.P) and compared to literature values. The method offers several advantages such as exclusive stereoselectivity, short reaction time, good yield, mild reaction conditions, and simple operational procedure.
Modular synthesis of (E)-cinnamaldehydes directly from allylarenes via a metal-free DDQ-mediated oxidative process
Xu, Ting-Ting,Jiang, Tao-Shan,Han, Xiao-Lan,Xu, Yuan-Hong,Qiao, Jin-Ping
, p. 5350 - 5358 (2018/08/03)
An efficient synthesis of (E)-cinnamaldehydes by a metal-free DDQ-mediated oxidative transformation of allylarenes was developed. The protocol provides a practical method to prepare diverse (E)-cinnamaldehydes with broad functional group tolerance in good to excellent yields, including easy access to natural products randainal and geranyloxy sinapyl aldehyde from plant extracts. Finally, the mechanism of a single-electron transfer process was proposed.
Direct oxidative conversion of 3-aryl propionaldehydes to 3-aryl acroleins promoted by SOMO catalysis
Zhu, Jin,Yu, Shunting,Lu, Wenchao,Deng, Jing,Li, Jian,Wang, Wei
scheme or table, p. 1207 - 1209 (2012/03/26)
A new direct oxidative transformation of 3-aryl propionaldehydes to 3-aryl acroleins promoted by SOMO catalysis has been realized with high efficiency under mild reaction conditions.
Efficient palladium(II) catalysis under air. Base-free oxidative heck reactions at room temperature or with microwave heating
Lindh, Jonas,Enquist, Per-Anders,Pilotti, Ake,Nilsson, Peter,Larhed, Mats
, p. 7957 - 7962 (2008/02/13)
(Figure Presented) Scope and limitations of the base-free oxidative Heck reaction with arylboronic acids have been explored. Under our conditions, the dmphen-palladium(II)-catalyzed arylation proceeded with air or p-benzoquinone as reoxidants of palladium(0). We found that ambient temperature and mild aerobic conditions allow for the use of substrates sensitive to palladium(II)-catalyzed oxidation. Oxidative Heck couplings, employing different arylboronic acids, were smoothly and regioselectively conducted with both electron-rich and electron-poor olefins, providing high yields even with disubstituted butyl methacrylate, sensitive acrolein, and a vinylboronate ester. Controlled microwave processing was used to reduce reaction times from hours to minutes both in small scale and in 50 mmol scale batch processes.
Catalytic synthesis of γ-lactams via direct annulations of enals and N-sulfonylimines
He, Ming,Bode, Jeffrey W.
, p. 3131 - 3134 (2007/10/03)
(Chemical Equation Presented) Cinnamaldehydes and N-sulfonylimines undergo direct annulations to cis-disubstituted γ-lactams via the intermediacy of catalytically generated homoenolates. Critical to the success of this process was overcoming inhibition of the N-heterocyclic carbene catalyst by the electrophilic imines. The overall process proceeds with good yields and diastereoselectivites and requires no stoichiometric reagents or additives.
Chemoselective Heck arylation of acrolein diethyl acetal catalyzed by an oxime-derived palladacycle
Nájera, Carmen,Botella, Luis
, p. 9688 - 9695 (2007/10/03)
A dimeric 4-hydroxyacetophenone oxime-derived palladacycle has been used as a very efficient precatalyst for the chemoselective arylation of acrolein diethyl acetal to give either cinnamaldehyde derivatives or 3-arylpropanoate esters by proper choice of the reaction conditions. The synthesis of cinnamaldehyde derivatives can be performed by Heck reaction of acrolein diethyl acetal with iodo-, bromo- or chloroarenes in N,N-dimethylacetamide (DMA) using K2CO3 as base at 120°C and tetra-n-butylammonium acetate (TBAA) and KCl as additives, followed by acid workup. In the case of 3-arylpropanoate esters the corresponding arylation of acrolein diethyl acetal with iodoarenes can be performed at 90°C in aqueous DMA using (dicylohexyl)methylamine as base, whereas for bromoarenes the reaction has to be performed at 120°C using tetra-n-butylammonium bromide (TBAB) as additive. Alternatively, this process can be performed under microwave irradiation. These couplings take place in good yields and with lower catalyst loading than with palladium(II) acetate as well as in shorter reaction times and with lower excess of acrolein diethyl acetal.
An efficient palladium-catalyzed synthesis of cinnamaldehydes from acrolein diethyl acetal and aryl iodides and bromides
Battistuzzi, Gianfranco,Cacchi, Sandro,Fabrizi, Giancarlo
, p. 777 - 780 (2007/10/03)
(Matrix presented) The reaction of aryl iodides and bromides with acrolein diethyl acetal in the presence of Pd(OAc)2, nBu 4NOAc, K2CO3, KCl, and DMF, at 90°C until the disappearance of the acetal followed by the addition of 2 N HCl to the crude reaction mixture, affords cinnamaldehydes in good to high yields. A variety of functional groups are tolerated in the aryl halides, including ether, aldehyde, ketone, ester, dialkylamino, nitrile, and nitro groups. The presence of substituents close to the oxidative addition site does not hamper the reaction.
Heck Arylation of α,β-Unsaturated Aldehydes
Nejjar,Pinel,Djakovitch
, p. 612 - 619 (2007/10/03)
The Heck arylation of α,β-unsaturated aldehydes is strongly dependent on the catalyst, the solvent and the base. Optimized conditions yielded either selectively cinnamyl derivatives (83%) or double arylation products (88% based on aryl conversion). A new α-arylation of β,β-disubstituted acrolein is also realized.
1-Tributylstannyl-3,3-diethoxyprop-1-ene as a d3 Acrolein Equivalent
Parrain, Jean-Luc,Duchene, Alain,Quintard, Jean-Paul
, p. 187 - 189 (2007/10/02)
1-Tributylstannyl-3,3-diethoxyprop-1-ene has proved to be a readily available β-formylvinyl anion equivalent which under mild experimental conditions gives ready access to cinnamic skeletons and 4-oxo- or 6-oxo-α,β-enals.
