C2 to C6 biobased carbonyl platforms for fine chemistry

• Jingjing Jiang,
• Muhammad Noman Haider Tariq,
• Florence Popowycz,
• Yanlong Gu and
• Yves Queneau

Beilstein J. Org. Chem. 2025, 21, 2103–2172, doi:10.3762/bjoc.21.165

• -hydroxypropan-2-one with acylacetonitrile towards furan derivatives using a Sc(OTf)3 catalyst. C2-based bifunctional acetals, such as glycolaldehyde diethyl acetal, α-bromoacetaldehyde acetal, and 1,4-dithiane-2,5-diol also take part in the reaction as counterpart reagents. The well-known fungicide fenfuram was

1,4-Dithianes: attractive C2-building blocks for the synthesis of complex molecular architectures

• Bram Ryckaert,
• Ellen Demeyere,
• Frederick Degroote,
• Hilde Janssens and
• Johan M. Winne

Beilstein J. Org. Chem. 2023, 19, 115–132, doi:10.3762/bjoc.19.12

• the commercially available 1,4-dithiane-2,5-diol (4) [26]. The diol 4 is commercially available in large quantities and is formally also a 1,4-dithiane derivative, but except for its dehydration to 1,4-dithiin, it is almost exclusively used as a source of mercapto acetaldehyde (of which it is a direct

Synthetic strategies toward 1,3-oxathiolane nucleoside analogues

• Umesh P. Aher,
• Dhananjai Srivastava,
• Girij P. Singh and
• Jayashree B. S

Beilstein J. Org. Chem. 2021, 17, 2680–2715, doi:10.3762/bjoc.17.182

• diastereomers by silica gel column chromatography and reaction with lead tetraacetate provided the key oxathiolane derivative 31. In 1995, Jin et al. [46] carried out the reaction of 1,4-dithiane-2,5-diol (3q) with glyoxylic acid (3g) hydrate at reflux temperature in tert-butyl methyl ether, which provided the

• acid derivatives to test the impact of a chiral auxiliary on N-glycosylation. Compound 50 was synthesized by ozonolysis of alkene 3rb, followed by reaction of aldehyde (generated in situ from alkene) with 1,4-dithiane-2,5-diol (3q). The use of lactic acid derivatives provided both enantiomers of

• highly effective crystallization-induced DKR to achieve an efficient synthesis of enantiomerically pure oxathiolane-based lactol 56a from ʟ-menthyl glyoxylate (3h) monohydrate and 1,4-dithiane-2,5-diol (3q, Scheme 17). The investigation proved that the base TEA was capable of effecting the equilibration

Synthesis of chiral 3-substituted 3-amino-2-oxindoles through enantioselective catalytic nucleophilic additions to isatin imines

• Hélène Pellissier

Beilstein J. Org. Chem. 2018, 14, 1349–1369, doi:10.3762/bjoc.14.114

• asymmetric formal [3 + 2] annulation reaction between N-Boc-isatin imines 3 and 1,4-dithiane-2,5-diol (53) as equal equivalent of 2-mercaptoacetaldehyde [78]. The domino reaction catalyzed by chiral tertiary amine-squaramide catalyst 54 began with the addition of 2-mercaptoacetaldehyde to isatin imine 3

• cinchona alkaloid-derived thiourea. Aza-Henry reaction of N-Boc-isatin imines with nitromethane catalyzed by a bifunctional guanidine. Domino addition/cyclization reaction of N-Boc-isatin imines with 1,4-dithiane-2,5-diol (53) catalyzed by a tertiary amine-squaramide. Nickel-catalyzed additions of methanol

Stereoselective amine-thiourea-catalysed sulfa-Michael/nitroaldol cascade approach to 3,4,5-substituted tetrahydrothiophenes bearing a quaternary stereocenter

• Sara Meninno,
• Chiara Volpe,
• Giorgio Della Sala,
• Amedeo Capobianco and
• Alessandra Lattanzi

Beilstein J. Org. Chem. 2016, 12, 643–647, doi:10.3762/bjoc.12.63

• nitroalkenes and commercially available 1,4-dithiane-2,5-diol to 3,4,5-substituted tetrahydrothiophenes, bearing a quaternary stereocenter, is presented. A secondary amine thiourea derived from (R,R)-1,2-diphenylethylamine was found to be the most effective catalyst when using trans-β-methyl-β-nitrostyrenes

• report on a dynamic system combining a 1,1,3,3-tetramethylguanidine (TMG)/ZnI2-catalyzed diastereoselective cascade sulfa-Michael/nitroaldol reaction followed by lipases catalyzed kinetic resolution using two representative trans-β-methyl-β-nitrostyrenes and 1,4-dithiane-2,5-diol as reagents [21]. One

• [22] with 1,4-dithiane-2,5-diol. Based on all above considerations and prompted by our interest in asymmetric synthesis of functionalized tetrahydrothiophenes [14], we wondered whether we could use bifunctional organocatalysts to develop a diastereo- and enantioselective cascade sulfa-Michael

An efficient synthesis of N-substituted 3-nitrothiophen-2-amines

• Sundaravel Vivek Kumar,
• Shanmugam Muthusubramanian,
• J. Carlos Menéndez and
• Subbu Perumal

Beilstein J. Org. Chem. 2015, 11, 1707–1712, doi:10.3762/bjoc.11.185

• , 28040 Madrid, Spain 10.3762/bjoc.11.185 Abstract A novel protocol for the synthesis of 3-nitro-N-aryl/alkylthiophen-2-amines in good yields from the reaction of α-nitroketene N,S-aryl/alkylaminoacetals and 1,4-dithiane-2,5-diol in the presence of K2CO3 in refluxing ethanol is described. This

• associated with the lack of regioselectivity and difficult isomer separation [23]. Other methods for the synthesis of 2,3-disubsituted thiophenes include the reactions of (i) 1,4-dithiane-2,5-diol with nitroalkenes [24], activated nitriles [25] and cyanoacetamide [26]; (ii) 3-nitrothiophene with Grignard

• goals of green chemistry [32]. In this context, we wish to report herein a new and efficient synthesis of 3-nitro-N-aryl/alkylthiophen-2-amines based on domino reactions between α-nitroketene N,S-aryl/alkylaminoacetals and 1,4-dithiane-2,5-diol, the dimer of 2-mercaptoacetaldehyde (Scheme 2). This work

Thiazole formation through a modified Gewald reaction

• Carl J. Mallia,
• Lukas Englert,
• Gary C. Walter and
• Ian R. Baxendale

Beilstein J. Org. Chem. 2015, 11, 875–883, doi:10.3762/bjoc.11.98

• The synthesis of thiazoles and thiophenes starting from nitriles, via a modified Gewald reaction has been studied for a number of different substrates. 1,4-Dithiane-2,5-diol was used as the aldehyde precursor to give either 2-substituted thiazoles or 2-substituted aminothiophenes depending on the

• substitution of the α-carbon to the cyano group. Keywords: design of experiment (DOE); 1,4-dithiane-2,5-diol; Gewald reaction; thiazole; thiophene; Introduction Thiazoles are privileged motifs which are encountered in many naturally occurring bioactive compounds and pharmaceuticals with indications in a

• an effecient way of synthesising 2-subsituted thiazoles from readily available, air stable 1,4-dithiane-2,5-diol (10) as a precursor for 2-mercaptoacetaldehyde. Experimental See Supporting Information File 1 for full experimental data. Selected examples of biologically active thiazole containing

An overview of the synthetic routes to the best selling drugs containing 6-membered heterocycles

• Marcus Baumann and
• Ian R. Baxendale

Beilstein J. Org. Chem. 2013, 9, 2265–2319, doi:10.3762/bjoc.9.265

• between glyoxilic acid monohydrate (3.13) and 1,4-dithiane-2,5-diol (3.14) (Scheme 33) [87]. Subsequent acetylation of the hydroxy group followed by ester formation using (−)-L-menthol permits crystallisation separation of the two diastereoisomers. The use of bis-TBDMS-cytosine as a coupling partner in