N-Sulfenylsuccinimide/phthalimide: an alternative sulfenylating reagent in organic transformations

• Fatemeh Doraghi,
• Seyedeh Pegah Aledavoud,
• Mehdi Ghanbarlou,
• Bagher Larijani and
• Mohammad Mahdavi

Beilstein J. Org. Chem. 2023, 19, 1471–1502, doi:10.3762/bjoc.19.106

• tetrahydropyrans 88 (Scheme 36) [70]. In this protocol, by controlling acid catalyst (camphorsulfonic acid (CSA) or trifluoromethanesulfonic acid (TfOH)), two different products were achieved and tetrahydrofurans 87 could be converted to tetrahydropyrans 88 by stereoselective rearrangement. In the same year, Zhu

Non-noble metal-catalyzed cross-dehydrogenation coupling (CDC) involving ether α-C(sp³)–H to construct C–C bonds

• Hui Yu and
• Feng Xu

Beilstein J. Org. Chem. 2023, 19, 1259–1288, doi:10.3762/bjoc.19.94

• copper is to activate the 1,3-dicarbonyl compounds through complexation that leads to a highly diastereoselective nucleophilic addition. Scheidt et al. reported an enantioselective Cu-catalyzed intramolecular cross-dehydrogenative coupling approach to substituted tetrahydropyrans with excellent yields

• tetrahydropyrans. CDC of thiazole with cyclic ethers. Cu(I)-catalyzed oxidative alkenylation of simple ethers. Cross-dehydrogenation coupling of isochroman C(sp3)–H bonds with anisole C(sp2)–H bonds. Pd(OAc)2/Cu(OTf)2-catalyzed arylation of α-C(sp3)–H bonds of ethers. Cu-catalyzed C(sp3)–H/C(sp2)–H activation

Photoredox catalysis harvesting multiple photon or electrochemical energies

• Mattia Lepori,
• Simon Schmid and
• Joshua P. Barham

Beilstein J. Org. Chem. 2023, 19, 1055–1145, doi:10.3762/bjoc.19.81

Advances in mercury(II)-salt-mediated cyclization reactions of unsaturated bonds

• Sumana Mandal,
• Raju D. Chaudhari and
• Goutam Biswas

Beilstein J. Org. Chem. 2021, 17, 2348–2376, doi:10.3762/bjoc.17.153

• fused polycyclic ethers by the treatment of a catalytic amount of Hg(TFA)2 with suitable starting material was demonstrated by Tan et al. [89]. They had reported a Hg(II)-catalyzed intramolecular trans-etherification reaction of 2-hydroxy-1-(γ-methoxyallyl)tetrahydropyrans 118 and 120 to the

Prins cyclization-mediated stereoselective synthesis of tetrahydropyrans and dihydropyrans: an inspection of twenty years

• Asha Budakoti,
• Pradip Kumar Mondal,
• Prachi Verma and
• Jagadish Khamrai

Beilstein J. Org. Chem. 2021, 17, 932–963, doi:10.3762/bjoc.17.77

• reaction rate and yield of the reaction. In a related study, the synthesis of polysubstituted tetrahydropyrans was described by Amberlyst® 15-catalyzed cyclization of homoallyl alcohol 107 and aldehydes 108. This method was further employed for the synthesis of highly substituted tetrahydropyrans with

• addition to construct a homoallylic alcohol, followed by Prins cyclization to furnish 2,3,4,5,6-pentasubstituted tetrahydropyrans 137 using β,γ-unsaturated N-acyloxazolidin-2-ones 134 as a key precursor [67]. In this Evans aldol−Prins (EAP) protocol, four new σ-bonds and five contiguous stereocenters were

• -workers’ stereoselective approach for the synthesis of highly substituted tetrahydropyrans through an Evans aldol−Prins cyclization strategy. Ene-IMSC strategy by Marko and Leroy for the synthesis of tetrahydropyran. Marko and Leroy’s strategy for the synthesis of tetrahydropyrans 146. Sakurai

Syntheses of spliceostatins and thailanstatins: a review

• William A. Donaldson

Beilstein J. Org. Chem. 2020, 16, 1991–2006, doi:10.3762/bjoc.16.166

• with their complex structure, a number of total syntheses have been reported. This review will compare the synthetic strategies reported through the end of 2019. Keywords: antiproliferative; polyketide natural products; tetrahydropyrans; total synthesis; Introduction The spliceostatins/thailanstatins

Stereoselective nucleophilic addition reactions to cyclic N-acyliminium ions using the indirect cation pool method: Elucidation of stereoselectivity by spectroscopic conformational analysis and DFT calculations

• Koichi Mitsudo,
• Junya Yamamoto,
• Tomoya Akagi,
• Atsuhiro Yamashita,
• Masahiro Haisa,
• Kazuki Yoshioka,
• Hiroki Mandai,
• Koji Ueoka,
• Christian Hempel,
• Jun-ichi Yoshida and
• Seiji Suga

Beilstein J. Org. Chem. 2018, 14, 1192–1202, doi:10.3762/bjoc.14.100

• form product, because an attack from another side would lead to a more unstable product with a twist form [13]. As a close study, Woerpel reported a diastereoselective substitution reaction for synthesizing disubstituted tetrahydropyrans via six-membered oxocarbenium ions generated in situ from

The direct oxidative diene cyclization and related reactions in natural product synthesis

• Juliane Adrian,
• Leona J. Gross and
• Christian B. W. Stark

Beilstein J. Org. Chem. 2016, 12, 2104–2123, doi:10.3762/bjoc.12.200

• ][16][17]. In addition, for Ru(VIII) [17][18][19] and Mn(VII) [21] it has been shown that also 1,6-dienes serve as substrates and can thus be directly converted to tetrahydropyrans [20][21][22]; ruthenium tetroxide even oxidizes 1,7-dienes to oxepans [23]. However, it has to be noted that the latter

Copper-catalysed asymmetric allylic alkylation of alkylzirconocenes to racemic 3,6-dihydro-2H-pyrans

• Emeline Rideau and
• Stephen P. Fletcher

Beilstein J. Org. Chem. 2015, 11, 2435–2443, doi:10.3762/bjoc.11.264

• racemic cyclic allyl halides, such as 1 (Scheme 1a) [26][27]. Tetrahydropyrans are a common motif in natural products and pharmaceuticals and are useful synthetic intermediates. However, the direct asymmetric derivatization of pyrans is rare [28] and enantiomerically enriched tetrahydropyrans are often

Visible-light-induced bromoetherification of alkenols for the synthesis of β-bromotetrahydrofurans and -tetrahydropyrans

• Run Lin,
• Hongnan Sun,
• Chao Yang,
• Youdong Yang,
• Xinxin Zhao and
• Wujiong Xia

Beilstein J. Org. Chem. 2015, 11, 31–36, doi:10.3762/bjoc.11.5

• photoredox-catalyzed bromoetherification of alkenols is described. This approach, with CBr4 as the bromine source through generation of bromine in situ, provides a mild and operationally simple access to the synthesis of β-bromotetrahydrofurans and -tetrahydropyrans with high efficiency and regioselectivity

• 31% (Table 1, entry 2). We have reported the bromoetherification of compound 1a as an example in our previous article [16]. However, considering the value of this strategy for the synthesis of β-bromotetrahydrofurans and -tetrahydropyrans, further research were carried out to optimize the reaction

• submitted to the optimized reaction conditions. As can be seen in Table 3, various styrenes were reacted efficiently to form the substituted tetrahydropyrans in high yield via 6-endo bromoetherification (Table 3, entries 1 and 2). Furthermore, not only primary alcohols but also secondary alcohols were

Recent advances in the electrochemical construction of heterocycles

• Robert Francke

Beilstein J. Org. Chem. 2014, 10, 2858–2873, doi:10.3762/bjoc.10.303

• number of 2-aryl-1,3-oxazolidines and 2-aryl-1,3-oxazinanes. An intriguing example for the intramolecular cyclization of alkoxycarbenium species has been reported recently by Suga, Yoshida et al. [56]. Unsaturated thioacetals 31 were converted anodically to 2,4-substituted tetrahydropyrans 32 using a

Chiral phosphines in nucleophilic organocatalysis

• Yumei Xiao,
• Zhanhu Sun,
• Hongchao Guo and
• Ohyun Kwon

Beilstein J. Org. Chem. 2014, 10, 2089–2121, doi:10.3762/bjoc.10.218

Relay cross metathesis reactions of vinylphosphonates

• Raj K. Malla,
• Jeremy N. Ridenour and
• Christopher D. Spilling

Beilstein J. Org. Chem. 2014, 10, 1933–1941, doi:10.3762/bjoc.10.201

• of vinylphosphonate 21a with 4-fluorostyrene and 4-benzyloxystyrene gave the tetrahydropyrans 26 and 7, respectively. Tetrahydropyran 7 is a known intermediate and can be converted to centrolobine by hydrogenation [17]. Surprisingly, the dimer 27 was isolated in small amounts (~20%) from the reaction

Efficient, highly diastereoselective MS 4 Å-promoted one-pot, three-component synthesis of 2,6-disubstituted-4-tosyloxytetrahydropyrans via Prins cyclization

• Naseem Ahmed and
• Naveen Kumar Konduru

Beilstein J. Org. Chem. 2012, 8, 177–185, doi:10.3762/bjoc.8.19

• -hydroxytetrahydropyran in excellent yields (95–96%). Keywords: aromatic homoallylic alcohols; 2,6-disubstituted-4-tosyloxytetrahydropyrans; MS 4 Å; Prins cyclization; PTSA; Introduction Substituted tetrahydropyrans are common structural motifs in numerous biological molecules and natural products that include

• phorboxazoles (A and B) [1], (−)-centrolobine [2], GEX1A/herboxidiene [3], bryostatins [4], and pheromones [5] (Figure 1). Tetrahydropyran derivatives are also used as materials in photographic films [6] and host–guest chemistry [7]. In particular, 2,4,6-trisubstituted tetrahydropyrans have tremendous

• tetrahydropyrans [30]; however, this method is restricted to electron withdrawing groups containing aromatic homoallylic alcohols. Similarly, She et al. recently have reported a new approach for the synthesis of 2,4,6-trisubstituted tetrahydropyrans via a Prins cyclization [31]. With this method, both symmetrical

A comparative study of the Au-catalyzed cyclization of hydroxy-substituted allylic alcohols and ethers

• Berenger Biannic,
• Thomas Ghebreghiorgis and
• Aaron Aponick

Beilstein J. Org. Chem. 2011, 7, 802–807, doi:10.3762/bjoc.7.91

• Berenger Biannic Thomas Ghebreghiorgis Aaron Aponick Department of Chemistry, University of Florida, P.O. Box 117200, Gainesville, FL 32611, U.S.A 10.3762/bjoc.7.91 Abstract The Au(I)-catalyzed cyclization of hydroxyallylic ethers to form tetrahydropyrans is reported. Employing (acetonitrile)[(o

• from our laboratory and others have demonstrated that unsaturated alcohols, such as allylic and propargylic alcohols, are reactive substrates that readily participate in dehydrative formal SN2' reactions [11][12][13][14][15][16][17][18][19][20][21][22][23][24][25]. The formation of tetrahydropyrans is

• more synthetically useful substrates. Conclusion In conclusion, it has been demonstrated that a variety of allylic ethers undergo Au-catalyzed formal SN2' reactions to form tetrahydropyrans. The reaction of allylic alcohols appears to be faster, although the leaving group is traditionally not

The preparation of 3-substituted-1,5-dibromopentanes as precursors to heteracyclohexanes

• Bryan Ringstrand,
• Martin Oltmanns,
• Jeffrey A. Batt,
• Aleksandra Jankowiak,
• Richard P. Denicola and
• Piotr Kaszynski

Beilstein J. Org. Chem. 2011, 7, 386–393, doi:10.3762/bjoc.7.49

• Łódź, Tamka 12, 91403 Łódź, Poland 10.3762/bjoc.7.49 Abstract The methodology to prepare 3-substituted 1,5-dibromopentanes I and their immediate precursors, which include 3-substituted 1,5-pentanediols VII or 4-substituted tetrahydropyrans VIII, is surveyed. Such dibromides I are important

• malonate diesters, while tetrahydropyrans 3c and 3d were obtained from tetrahydro-4H-pyran-4-one. The advantages and disadvantages of each route are discussed. Dibromides 1c and 1d were used to prepare sulfonium zwitterions 11c and 11d. Keywords: 1,5-dibromopentanes; heterocycles; methodology; synthesis

• ], while the latter from p-toluenesulfonyl chloride in the presence of a base such as pyridine [13][17][18][19][20]. Dibromides I can also be obtained by the ring-opening of tetrahydropyrans VIII under the same conditions employed for the diols VII [2][12][21][22], or via phase-transfer catalysis

Recent progress on the total synthesis of acetogenins from Annonaceae

• Nianguang Li,
• Zhihao Shi,
• Yuping Tang,
• Jianwei Chen and
• Xiang Li

Beilstein J. Org. Chem. 2008, 4, No. 48, doi:10.3762/bjoc.4.48

• . These include mono-tetrahydrofurans, adjacent bis-tetrahydrofurans, nonadjacent bis-tetrahydrofurans, tri-tetrahydrofurans, adjacent tetrahydrofuran-tetrahydropyrans, nonadjacent tetrahydrofuran-tetrahydropyrans, mono-tetrahydropyrans, and acetogenins containing only γ-lactone. This review emphasizes

• , ketones, epoxides, tetrahydrofurans (THF) and tetrahydropyrans (THP), may be present, as well as double and triple bonds. Thus several types of ACGs have been characterised, based on the nature of the functional groups which are present. These including mono-THF, adjacent bis-THF, nonadjacent bis-THF, tri

Synthesis of 2,6-trans- disubstituted 5,6-dihydropyrans from (Z)-1,5-syn-endiols

• Eric M. Flamme and
• William R. Roush

Beilstein J. Org. Chem. 2005, 1, No. 7, doi:10.1186/1860-5397-1-7

• -dihydropyrans. Furthermore, there are only limited reports describing the stereoselective synthesis of related tetrahydropyrans through cyclodehydration of enantiopure 1,5-diols substrates.[17] The challenge of synthesizing dihydropyrans 3 or ent-3 from 1,5-diols such as 2 lies in the differentiation of the two