Eschenmoser coupling reactions starting from primary thioamides. When do they work and when not?

• Lukáš Marek,
• Jiří Váňa,
• Jan Svoboda and
• Jiří Hanusek

Beilstein J. Org. Chem. 2023, 19, 808–819, doi:10.3762/bjoc.19.61

• ) as a polar aprotic solvent that can be easily distilled-off after the ECR under reduced pressure. The last complication with aromatic primary thioamides concerns their easy oxidation with electron-poor α-haloesters (acetoacetates and α-cyanoacetates). As early as in 1976 Potts and Marshall noticed

Tri(n-butyl)phosphine-promoted domino reaction for the efficient construction of spiro[cyclohexane-1,3'-indolines] and spiro[indoline-3,2'-furan-3',3''-indolines]

• Hui Zheng,
• Ying Han,
• Jing Sun and
• Chao-Guo Yan

Beilstein J. Org. Chem. 2022, 18, 669–679, doi:10.3762/bjoc.18.68

• . Additionally, the tri(n-butyl)phosphine-promoted domino annulation reaction of isatins and ethyl isatylidene cyanoacetates produced spiro[indoline-3,2'-furan-3',3''-indolines] in satisfactory yields. Keywords: isatin; spiro[cyclohexane-1,3'-indoline]; spiro[indoline-3,2'-furan-3',3''-indoline]; spirooxindole

• of the zwitterion A to the isatylidene malononitrile 2 and 3-(ethoxycarbonylmethylene)oxindole 4 results in the different regioselectivity in the formation of the spiro compounds 3 and 5. For further demonstrate the synthetic value of this procedure, ethyl isatylidene cyanoacetates 6 were also

• turned our attention to the examination of this unprecedented reaction of isatins with ethyl isatylidene cyanoacetates. At last, we successfully found that tri(n-butyl)phosphine promoted the reaction of ethyl isatylidene cyanoacetate 6a and isatin 7a always resulted in spiro[indoline-3,2'-furan-3',3

Methodologies for the synthesis of quaternary carbon centers via hydroalkylation of unactivated olefins: twenty years of advances

• Thiago S. Silva and
• Fernando Coelho

Beilstein J. Org. Chem. 2021, 17, 1565–1590, doi:10.3762/bjoc.17.112

• nucleophiles beyond the usually employed dicarbonyl compounds to cyanoacetates, nitroacetates, fluoroacetates, lactones, lactams, and aromatic and heteroaromatic carbonyl compounds. The reactions were carried out at higher temperatures (120 °C) than used in the previous protocols involving more reactive

Recent advances in transition-metal-catalyzed incorporation of fluorine-containing groups

• Xiaowei Li,
• Xiaolin Shi,
• Xiangqian Li and
• Dayong Shi

Beilstein J. Org. Chem. 2019, 15, 2213–2270, doi:10.3762/bjoc.15.218

• derivatives. Notably, in this process, a new method was developed for generating Ag[18F]F by using a sep-pak cartridge. In 2012, van Leeuwen and co-workers [45] described the synthesis of new enantiopure wide-bite-angle diphosphanes and their application in the asymmetric fluorination of α-cyanoacetates with

Dialkyl dicyanofumarates and dicyanomaleates as versatile building blocks for synthetic organic chemistry and mechanistic studies

• Grzegorz Mlostoń and
• Heinz Heimgartner

Beilstein J. Org. Chem. 2017, 13, 2235–2251, doi:10.3762/bjoc.13.221

• cyanoacetates as well as their bromo and dibromo derivatives are the most important starting materials. The first described method comprised the treatment of ethyl cyanoacetate (2a) with SeO2 at 120–125 °C, leading to E-1a in ca. 10% yield [4] (Scheme 1). More efficient syntheses of diverse dialkyl esters E-1

• were achieved in reactions of alkyl cyanoacetates 2 with SOCl2 in tetrahydrofuran (THF) at reflux temperature [5][6][7][8]. Unexpectedly, the attempted preparation of the di(tert-butyl) derivative was unsuccessful. The highest yield (90%) was obtained for E-1a when 2a was oxidized with I2 in the

• bicyclic piperazine (quinoxaline) derivative 73 in 61% yield [68] (Scheme 23). The analogous reaction with [(S)-pyrrolidin-2-yl]methylamine ((S)-prolinamine) with E-1a–c occurred smoothly in CH2Cl2 at room temperature yielding optically active (4-oxohexahydropyrrolo[1,2-a]pyrazin-3-ylidene)-2-cyanoacetates

The reductive decyanation reaction: an overview and recent developments

• Jean-Marc R. Mattalia

Beilstein J. Org. Chem. 2017, 13, 267–284, doi:10.3762/bjoc.13.30

• cyanoacetates (α-cyanoesters). These compounds are particularly versatile reagents in organic synthesis including multicomponent reactions [109][110][111][112][113]. However, like decarboxylation for related malonic ester or acetoacetates, an easy access to the removal of the cyano group should encourage future

• variety of mono- and dialkylated malononitriles but under these conditions, the reduction of cyanoacetates failed [115]. Synthetic applications of this methodology were later described [116][117][118]. Chiba et al. have developed a concise and stereoselective methodology for the preparation of highly

• ]. Selected examples are presented in Scheme 26. Excellent yields are obtained even if decyanation of cyanoacetates requires higher amounts of 78 (6 equiv) with extended reaction times (72 h). In line with this work, the authors prepared the tetra(iminophosphorano)-substituted bispyridinylidene 80, a new

1H-Imidazol-4(5H)-ones and thiazol-4(5H)-ones as emerging pronucleophiles in asymmetric catalysis

• Antonia Mielgo and
• Claudio Palomo

Beilstein J. Org. Chem. 2016, 12, 918–936, doi:10.3762/bjoc.12.90

• substrate; however, to date, the carbonyl components for these reactions are mostly restricted to 1,3-diones, β-ketoesters, malonates, α-cyanoacetates, 3-substitued oxindoles and related systems. Generally, enolizable esters or carboxylic acid derivatives have been challenging in this strategy, because

Synthesis and mesomorphic properties of calamitic malonates and cyanoacetates tethered to 4-cyanobiphenyls

• Katharina C. Kress,
• Martin Kaller,
• Kirill V. Axenov,
• Stefan Tussetschläger and
• Sabine Laschat

Beilstein J. Org. Chem. 2012, 8, 371–378, doi:10.3762/bjoc.8.40

• with methyl 3-chloro-3-oxopropionate or cyanoacetic acid, giving liquid-crystalline linear malonates and cyanoacetates. These compounds formed monotropic nematic phases at 62 °C down to ambient temperature upon cooling from the isotropic liquid. The mesomorphic properties were investigated by

• differential scanning calorimetry, polarizing optical microscopy and X-ray diffraction (WAXS). Keywords: cyanoacetates; 4-cyanobiphenyls; liquid crystals; malonates; nematic; Introduction Nematic liquid crystals display mesophases in which the molecules are oriented along one vector defined by the director

• malonates and cyanoacetates are well known as suitable ligands for strong coordination of main-group and transition metals [25]. Benzylidene derivatives of malonic esters, so called swallow-tailed liquid crystals, were described as forming smectic phases [26]. However, most work on liquid-crystalline

Synthesis of 2-substituted 9-oxa-guanines {5-aminooxazolo[5,4-d]pyrimidin- 7(6H)-ones} and 9-oxa-2-thio- xanthines {5-mercaptooxazolo[5,4-d]pyrimidin- 7(6H)-ones}

• Subrata Mandal,
• Wen Tai Li,
• Yan Bai,
• Jon D. Robertus and
• Sean M. Kerwin

Beilstein J. Org. Chem. 2008, 4, No. 26, doi:10.3762/bjoc.4.26

• prepared from the (acylamino)cyanoacetates 5b,c, which in turn were derived from ethyl cyanoglyoxylate oxime (4) by reduction followed by acylation by isobutyric anhydride or azidoacetyl chloride (Figure 3). Reaction of the aminooxazoles 3b,c with benzoylisothiocyanate afforded the thioureas 6b,c. Direct