Controlling the stereochemistry in 2-oxo-aldehyde-derived Ugi adducts through the cinchona alkaloid-promoted electrophilic fluorination

• Yuqing Wang,
• Gaigai Wang,
• Anatoly A. Peshkov,
• Ruwei Yao,
• Muhammad Hasan,
• Manzoor Zaman,
• Chao Liu,
• Stepan Kashtanov,
• Olga P. Pereshivko and
• Vsevolod A. Peshkov

Beilstein J. Org. Chem. 2020, 16, 1963–1973, doi:10.3762/bjoc.16.163

• bearing fluorine and nitrogen atoms involves the asymmetric addition of α-fluoro-β-ketoesters or α-fluoro-α-nitro esters to appropriate electrophiles [84][85][86][87][88][89]. Results and Discussion Initially, we prepared a series of Ugi adducts 8 by varying acid, 2-oxo-aldehyde, amine, and isocyanide

Synthesis of unnatural α-amino esters using ethyl nitroacetate and condensation or cycloaddition reactions

• Glwadys Gagnot,
• Vincent Hervin,
• Eloi P. Coutant,
• Sarah Desmons,
• Racha Baatallah,
• Victor Monnot and
• Yves L. Janin

Beilstein J. Org. Chem. 2018, 14, 2846–2852, doi:10.3762/bjoc.14.263

• -amino esters was achieved using gold(I) chemistry. Keywords: α-amino ester; α-nitro esters; cerium ammonium nitrate; cycloaddition; gold(I) cyclization; Introduction In the course of our work on an original synthesis of imidazo[1,2-a]pyrazin-3(7H)-one luciferins [1], a large variety of racemic α-amino

• the corresponding α-nitro esters 6a–s. Isopropanol was used instead of ethanol in order to decrease the incidence of a recurrent side product arising from a decarboxylation or a retro condensation of the partially reduced ester function (this side product was characterized in 1H NMR by two triplets at

• improvements were observed with these conditions. Other series of trials were made to improve the overall yields of the furan-bearing α-nitro esters 6n–r. We first tried to avoid the preparation of the acetals 5n or 5o and used the previously reported direct condensation between furfural (3n) and ethyl

Shelf-stable electrophilic trifluoromethylating reagents: A brief historical perspective

• Norio Shibata,
• Andrej Matsnev and
• Dominique Cahard

Beilstein J. Org. Chem. 2010, 6, No. 65, doi:10.3762/bjoc.6.65

• showed a clear advantage in the reaction with α-nitro esters; the reaction proceeded smoothly in CH2Cl2 in the presence of a catalytic amount of CuCl2 (Scheme 28) [33]. Interestingly, 2-(2-iodophenyl)propan-2-ol formed as by-product in the reactions of 37 with the substrates could be isolated and

• -nitro esters. In particular, reagent 37 was found to be an effective trifluoromethylating agent. Under phase-transfer catalysis the β-keto esters derived from indanone, tetralone and pentanone in the presence of 37 gave the corresponding trifluoromethylated product in 42–67% yields. The new reagents

• with Ruppert’s reagent (Scheme 27) [33]. These reagents are shelf-stable, non-explosive under ambient conditions but should not be heated as solid materials. These new electrophilic trifluoromethylating reagents were initially evaluated in reactions with carbonyl compounds such as β-keto esters and α