38405-81-1Relevant articles and documents
Catalytic addition of pyrazoles to but-3-enenitrile
Hayotsyan,Khachatryan,Attaryan,Hasratyan
, (2015)
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Selective and nonselective aza-michael additions catalyzed by a chiral zirconium bis-diketiminate complex
El-Zoghbi, Ibrahim,Kebdani, Myriam,Whitehorne, Todd J. J.,Schaper, Frank
, p. 6986 - 6995 (2014/01/06)
Reaction of the chiral bis-diketiminate complex rac- or (R,R)-C 6H10(nacnacXyl)2ZrCl2 with AgOTf yielded the corresponding bis-triflate complex. The complex geometry changes from distorted octahedral in the dichloride complex to a pseudotetrahedral coordination involving π coordination of the diketiminate ligands. The bis-triflate complex is highly active for aza-Michael additions with turnover frequencies of 20000/h for the addition of morpholine to acrylonitrile and 1000/h for the addition of morpholine to methacrylonitrile. The enantioselectivities of the latter reaction in various solvents were low, never surpassing 19% ee. The reaction is first-order in olefin concentration and second order in amine concentration, which is explained by its participation as a base in the reaction mechanism. The presence of catalytic amounts of triethylamine slightly increases the observed rate constants and reduces the reaction order in amine to first order. Other activated alkenes such as methacrylonitrile, crotonitrile, methyl acrylate, and cyclohexenone can be employed, but no reactivity is observed toward styrene or vinyl ethers. Primary amines, secondary amines, and anilines can be employed as nucleophiles with activities correlating with their nucleophilicity, but the catalyst is unstable in the presence of alcohols.
Addition of amines and phenols to acrylonitrile derivatives catalyzed by the POCOP-type pincer complex [{κP,κC, κP-2,6-(i-Pr2PO)2C6H 3}Ni(NCMe)][OSO2CF3]
Lefvre, Xavier,Durieux, Guillaume,Lesturgez, Stéphanie,Zargarian, Davit
experimental part, p. 1 - 7 (2011/03/23)
The pincer-type complex [{κP,κC, κP-2,6-(i-Pr2PO)2C6H 3}Ni(NCMe)][OSO2CF3] (1) can serve as a precatalyst for the regioselective, anti-Markovnikov addition of nucleophiles to activated olefins. The catalyzed additions of aliphatic amines to acrylonitrile, methacrylonitrile, and crotonitrile proceed at room temperature and give quantitative yields of products resulting from the formation of C-N bonds. On the other hand, aromatic amines or alcohols are completely inert toward methacrylonitrile and crotonitrile, and much less reactive toward acrylonitrile, requiring added base, heating, and extended reaction times to give good yields. The catalytic reactivities of 1 are thought to arise from the substitutional lability of the coordinated acetonitrile that allows competitive coordination of the nitrile moiety in the olefinic substrates; this binding enhances the electrophilicity of the CC moiety, rendering them more susceptible to attack by nucleophiles. In some cases, RCN → Ni binding results in double bond isomerization/migration (allyl cyanide) or attack of nucleophiles at the nitrile moiety (cinnamonitrile and 4-cyanostyrene). Reaction of morpholine with 1 at 60 °C led to formation of the amidine derivative 2 that has been characterized by X-ray crystallography.
