- Cyanide-Free and Broadly Applicable Enantioselective Synthetic Platform for Chiral Nitriles through a Biocatalytic Approach
-
A cyanide-free platform technology for the synthesis of chiral nitriles by biocatalytic enantioselective dehydration of a wide range of aldoximes is reported. The nitriles were obtained with high enantiomeric excess of >90 % ee (and up to 99 % ee) in many cases, and a “privileged substrate structure” with respect to high enantioselectivity was identified. Furthermore, a surprising phenomenon was observed for the enantiospecificity that is usually not observed in enzyme catalysis. Depending on whether the E or Z isomer of the racemic aldoxime substrate was employed, one or the other enantiomer of the corresponding nitrile was formed preferentially with the same enzyme.
- Betke, Tobias,Rommelmann, Philipp,Oike, Keiko,Asano, Yasuhisa,Gr?ger, Harald
-
supporting information
p. 12361 - 12366
(2017/09/06)
-
- Photoinduced, Copper-Catalyzed Carbon-Carbon Bond Formation with Alkyl Electrophiles: Cyanation of Unactivated Secondary Alkyl Chlorides at Room Temperature
-
We have recently reported that, in the presence of light and a copper catalyst, nitrogen nucleophiles such as carbazoles and primary amides undergo C-N coupling with alkyl halides under mild conditions. In the present study, we establish that photoinduced, copper-catalyzed alkylation can also be applied to C-C bond formation, specifically, that the cyanation of unactivated secondary alkyl chlorides can be achieved at room temperature to afford nitriles, an important class of target molecules. Thus, in the presence of an inexpensive copper catalyst (CuI; no ligand coadditive) and a readily available light source (UVC compact fluorescent light bulb), a wide array of alkyl halides undergo cyanation in good yield. Our initial mechanistic studies are consistent with the hypothesis that an excited state of [Cu(CN)2]- may play a role, via single electron transfer, in this process. This investigation provides a rare example of a transition metal-catalyzed cyanation of an alkyl halide, as well as the first illustrations of photoinduced, copper-catalyzed alkylation with either a carbon nucleophile or a secondary alkyl chloride.
- Ratani, Tanvi S.,Bachman, Shoshana,Fu, Gregory C.,Peters, Jonas C.
-
supporting information
p. 13902 - 13907
(2016/01/15)
-
- Efficient dehydration of aldoximes to nitriles with TiCl3(OTf)
-
Aromatic, alicyclic, olefinic as well as heterocyclic aldoximes, were dehydrated to their corresponding nitriles with 0.15 molar equivalents of TiCl3(OTf) in sealed tube at 80 °C in 85-97% yield.
- Iranpoor,Zeynizadeh
-
p. 2747 - 2752
(2007/10/03)
-
- An elimination reaction of N-carbomethoxy-N,N-dimethylhydrazonium salts to alkyl nitriles
-
A new kind of elimination of hydrazonium salts to alkyl nitriles has been developed. The reaction of hydrazones and chloroformates results in the formation of hydrazonium salts, which react in situ with water to afford alkyl nitriles. The elimination is adapted to a range of solvents and gives good yields of α-secondary and tertiary alkyl-substituted nitriles.
- Xiao, Zejun,Timberlake, Jack W.
-
p. 12715 - 12720
(2007/10/03)
-
- SYNTHESIS OF (+/-)-IRCINIANIN, A MARINE SPONGE SESTERTERPENE
-
A biogenetic-type synthesis of (+-)-ircinianin (1) via intramolecular Diels-Alder reaction of 2 is described.
- Takeda, Kei,Sato, Masa-aki,Yoshii, Eiichi
-
p. 3903 - 3906
(2007/10/02)
-
- Photoreactions of α-sulfonyloxyketones
-
Earlier work on the photochemistry of α-sulfonyloxyketones uncovered their propensity to form the corresponding α-ketocarbonium ions on photolysis.Typical reactions such as intramolecular cyclizations, carbonium ion rearrangements, and solvent trapping were found.This paper describes an attempt to extend this reaction to a general synthetic technique for polyene cyclizations.During the course of this work two other major reaction pathways were found.The first is an α-keto carbonium ion to acylium ion rearrangement and the second is a photoreduction-elimination process that leads to an α-keto radical rather than the corresponding cation.
- Charlton, James Leslie.,Lai, Hoi Kiong.,Lypka, Gerald Nicholas
-
p. 458 - 462
(2007/10/02)
-