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

• highly reactive electrophiles. The homologous 1,4-dithianes or 1,4-dioxanes are readily available as simple building blocks, but also undergo a swift β-elimination following the metalation of one of their ring carbons, again limiting their appeal as building blocks [16][17]. In his landmark synthesis of

Reductive opening of a cyclopropane ring in the Ni(II) coordination environment: a route to functionalized dehydroalanine and cysteine derivatives

• Oleg A. Levitskiy,
• Olga I. Aglamazova,
• Yuri K. Grishin and
• Tatiana V. Magdesieva

Beilstein J. Org. Chem. 2022, 18, 1166–1176, doi:10.3762/bjoc.18.121

• recently, two publications from the Werz group appeared concerning anodic activation of donor–acceptor cyclopropanes followed by their functionalization with arenes [43] or yielding oxy-ketones or 1,2-dioxanes [44]; the latter process was inspired by a previous report of Buriez [45]. The anodic

Rearrangements of organic peroxides and related processes

• Ivan A. Yaremenko,
• Vera A. Vil’,
• Dmitry V. Demchuk and
• Alexander O. Terent’ev

Beilstein J. Org. Chem. 2016, 12, 1647–1748, doi:10.3762/bjoc.12.162

• -diketones 283 (Scheme 84) [359][360]. The Kornblum–DeLaMare rearrangement of 1,2-dioxenes 284 [361], 1,2-dioxanes 286 [362], and tert-butyl peroxides 288 [330][363] produces 1,4-dicarbonyl compounds 285, 287, and 289, respectively (Scheme 85). These compounds are versatile starting substrates for the

• synthesis of various heterocyclic systems, such as furan, thiophene, and pyrrole derivatives. The reaction of unsymmetrical epoxy dioxanes 290a–d with triethylamine is accompanied by the 1,2-dioxane-ring opening to form 4-hydroxy-2,3-epoxy ketones 291a–d in high yields. The base catalysis involves the

The hydrolysis of geminal ethers: a kinetic appraisal of orthoesters and ketals

• Sonia L. Repetto,
• James F. Costello,
• Craig P. Butts,
• Joseph K. W. Lam and
• Norman M. Ratcliffe

Beilstein J. Org. Chem. 2016, 12, 1467–1475, doi:10.3762/bjoc.12.143

• limiting [26]. The overall rate of reaction can therefore be established by measuring the consumption of the geminal ether [27]. We present here kinetic data measured for a range of acyclic orthoformates, orthoacetates, 1,3-dioxolane orthoesters, oxanes, and 1,3-dioxanes (Figure 1), and consider the

Tandem processes promoted by a hydrogen shift in 6-arylfulvenes bearing acetalic units at ortho position: a combined experimental and computational study

• Mateo Alajarin,
• Marta Marin-Luna,
• Pilar Sanchez-Andrada and
• Angel Vidal

Beilstein J. Org. Chem. 2016, 12, 260–270, doi:10.3762/bjoc.12.28

• ]. Notably, thermally promoted H-shifts remain, to the best of our knowledge, completely unexplored in fulvene frameworks [17][18]. A part of our recent research focused on showing the special ability of cyclic acetalic functions (1,3-dioxolanes, thiolanes, oxathiolanes, dioxanes, dithianes, oxathianes) for

Cyclization–endoperoxidation cascade reactions of dienes mediated by a pyrylium photoredox catalyst

• Nathan J. Gesmundo and
• David A. Nicewicz

Beilstein J. Org. Chem. 2014, 10, 1272–1281, doi:10.3762/bjoc.10.128

• irradiation in the presence of oxygen, bicyclic endoperoxides were obtained [12]. Formation of the 1,2-dioxanes was presumed to occur via single electron oxidation of the diene by the excited state DCA followed by either 6-endo or 7-endo cyclization modes to generate a fleeting distonic cation radical species

• was observed 2w. Conclusion In the presence of an organic single electron photooxidant, a variety of dienes were demonstrated to undergo a cyclization/endoperoxidation cascade sequence to form 1,2-dioxanes. Requirements for successful diene reactivity are the presence of an oxidizable olefin and an

Synthesis of five- and six-membered cyclic organic peroxides: Key transformations into peroxide ring-retaining products

• Alexander O. Terent'ev,
• Dmitry A. Borisov,
• Vera A. Vil’ and
• Valery M. Dembitsky

Beilstein J. Org. Chem. 2014, 10, 34–114, doi:10.3762/bjoc.10.6

• .10.6 Abstract The present review describes the current status of synthetic five and six-membered cyclic peroxides such as 1,2-dioxolanes, 1,2,4-trioxolanes (ozonides), 1,2-dioxanes, 1,2-dioxenes, 1,2,4-trioxanes, and 1,2,4,5-tetraoxanes. The literature from 2000 onwards is surveyed to provide an update

• , and antitumor agents. Keywords: cyclic peroxides; 1,2-dioxanes; 1,2-dioxenes; 1,2-dioxolanes; ozonides; 1,2,4,5-tetraoxanes; 1,2,4-trioxanes; 1,2,4-trioxolanes; Introduction Approaches to the synthesis of five and six-membered cyclic peroxides, such as 1,2-dioxolanes I, 1,2,4-trioxolanes (ozonides

• ) II, 1,2-dioxanes III, 1,2-dioxenes IV, 1,2,4-trioxanes V, and 1,2,4,5-tetraoxanes VI, published from 2000 to present are reviewed. These compounds are widely used in synthetic and medicinal chemistry (Figure 1). In the last decade, two reviews on this rapidly progressing field were published by

A reductive coupling strategy towards ripostatin A

• Kristin D. Schleicher and
• Timothy F. Jamison

Beilstein J. Org. Chem. 2013, 9, 1533–1550, doi:10.3762/bjoc.9.175

• stereoselective fashion from displacement of a leaving group at C10, a means for the selective formation of a syn-1,3-diol at C11 and C13 is required. Rychnovsky has demonstrated that alkylation of 4-cyano-1,3-dioxanes (cyanohydrin acetonides) constitutes a practical and valuable approach to syn-1,3-diol

Anionic cascade reactions. One-pot assembly of (Z)-chloro-exo-methylenetetrahydrofurans from β-hydroxyketones

• István E. Markó and
• Florian T. Schevenels

Beilstein J. Org. Chem. 2013, 9, 1319–1325, doi:10.3762/bjoc.9.148

• , possessing unique structural features. Keywords: acetylene addition; dichloroethylene; dimerisation; dioxanes; tetrahydrofurans; Introduction Recently, we have shown that simple ketones reacted with 1,1-dichloroethylene, in the presence of potassium tert-butoxide, to afford rare (Z)-chloro-exo

• formation of the syn-dioxanes 37 and 38 respectively, albeit at the expense of the yield [32][33][34][35][36][37][38]. When the dimethyl adduct 6 was submitted to the same conditions, a new product [39][40][41][42][43][44][45] 41 was formed besides the dioxanes 39 and 40 (Scheme 7). Its structure was

• enol ether function, followed by 6-exo-trig cyclization, completes this sequence of events and provides the dioxane derivative 46. Interestingly, no reaction was observed when the spirocycle 41 and the dioxanes 35, 36 and 39 were reacted under acidic conditions, indicating that the final step is not

Synthesis and enzymatic evaluation of 2- and 4-aminothiazole- based inhibitors of neuronal nitric oxide synthase

• Graham R. Lawton,
• Haitao Ji,
• Pavel Martásek,
• Linda J. Roman and
• Richard B. Silverman

Beilstein J. Org. Chem. 2009, 5, No. 28, doi:10.3762/bjoc.5.28

• , TEA, HN(OMe)Me·HCl, CH2Cl2, 16 h; v) LAH, THF, 0 °C, 1 h; vi) (±)-17, CH2Cl2, NaHB(OAc)3, 1 h; vii) 4N HCl, dioxanes, rt, 16 h. Assembly of the 4-aminothiazole fragments. i) LiCH2CN, THF, 0 °C, 4 h; ii) (NH4)2S (aq), MeOH, 16 h; iii) ethyl brompyruvate (for R = H) or 30, MeOH, reflux, 5 h, then DIEA

• tautomerization and hydrolysis. i) MeOH, 30 min, then NaHB(OAc)3, rt, 1 h; ii) 4N HCl, dioxanes, rt, 16 h. Supporting Information Supporting Information features full experimental details for all synthetic steps, characterization of intermediates (1H NMR, 13C NMR, ESMS), details of Autodock analysis, details of