Tandem Hock and Friedel–Crafts reactions allowing an expedient synthesis of a cyclolignan-type scaffold

• Viktoria A. Ikonnikova,
• Cristina Cheibas,
• Oscar Gayraud,
• Alexandra E. Bosnidou,
• Nicolas Casaretto,
• Gilles Frison and
• Bastien Nay

Beilstein J. Org. Chem. 2024, 20, 162–169, doi:10.3762/bjoc.20.15

• ], in the presence of a nucleophilic species. Recently, we applied this idea to the rearrangement of 1-indanyl hydroperoxides into 2-substituted chromane derivatives, involving the nucleophilic allylation of the rearranged oxocarbenium intermediate (Scheme 1b) [12][13]. Furthermore, it is interesting to

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

• tricyclic chromane nucleus from 8-hydroxyisochromanes and 1,3-dicarbonyl compounds in the presence of Cu(OTf)2 and T+BF4− (Scheme 7b) [57]. The strategy has a wide range of applications and is highly diastereoselective, making it an attractive strategy for synthesizing related natural products. The role of

Efficient synthesis of pyrazolopyridines containing a chromane backbone through domino reaction

• Razieh Navari,
• Saeed Balalaie,
• Saber Mehrparvar,
• Fatemeh Darvish,
• Frank Rominger,
• Fatima Hamdan and
• Sattar Mirzaie

Beilstein J. Org. Chem. 2019, 15, 874–880, doi:10.3762/bjoc.15.85

• base led to a fused chromanyl-cyanopyridine. High selectivity, high atom economy, and good to high yields in addition to mild reaction conditions are the advantages of this approach. Keywords: chromane; domino reaction; fused heterocyclic skeletons; pyrazolopyridines; Introduction The synthesis of

• and provided access to fused heterocycles pyrazolopyridines containing chromane. The same reaction without base led to the formation of pyridochromanes 5a–d. The presented procedure provides several advantageous features including domino reaction character, one-pot procedure, high selectivity, mild

Assembly of fully substituted triazolochromenes via a novel multicomponent reaction or mechanochemical synthesis

• Robby Vroemans,
• Yenthel Verhaegen,
• My Tran Thi Dieu and
• Wim Dehaen

Beilstein J. Org. Chem. 2018, 14, 2689–2697, doi:10.3762/bjoc.14.246

• search for new methodologies towards the rapid assembly of chromene analogs is of utmost importance for many researchers. In this regard, 3-nitrochromenes are easily available building blocks for chromene and chromane derivatives and are highly reactive due to the presence of the nitroalkene moiety

(Thio)urea-mediated synthesis of functionalized six-membered rings with multiple chiral centers

• Giorgos Koutoulogenis,
• Nikolaos Kaplaneris and
• Christoforos G. Kokotos

Beilstein J. Org. Chem. 2016, 12, 462–495, doi:10.3762/bjoc.12.48

• combined with nucleophilic naphthols 188 and 189 to produce medicinally interesting chromane derivates 190 and 191 respectively. Zhao and co-workers employed the bifunctional cinchona-derived thiourea 181 to catalyze the tandem Henry–Michael reaction of nitromethane (101) to the enal 192, but the reaction

New metathesis catalyst bearing chromanyl moieties at the N-heterocyclic carbene ligand

• Agnieszka Hryniewicka,
• Szymon Suchodolski,
• Agnieszka Wojtkielewicz,
• Jacek W. Morzycki and
• Stanisław Witkowski

Beilstein J. Org. Chem. 2015, 11, 2795–2804, doi:10.3762/bjoc.11.300

• compounds even at 0 °C. It was also examined in more demanding systems such as conjugated dienes and polyenes. The catalyst is stable, storable and easy to purify. Keywords: chromane derivatives; metathesis catalyst; nitrogen heterocycles; olefin metathesis; Ru-carbene; Introduction Olefin metathesis is

• -enol [27]. Chromane 10 was nitrated with fuming nitric acid to give 6-nitrochromane 11 in 58% yield according to Mahdavian [28] (Scheme 1). Nitration using the Smith procedure [29] led to the expected nitrochromane 11, however, formation of an admixture of 5a,6-dinitrochromane was observed. Reduction

• scission of the less reactive C2–C3 double bond prevailed with complex 9 (Table 4, entry 4). This result could be explained by the higher affinity of the new catalyst toward electron-deficient olefins. It may also be assumed that the presence of the chromane system changes the electronic properties of the

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

• in 71% yield (the diastereoisomeric ratio was 1:1); the yield of 75b (n = 2) was 21% (the diastereoisomeric ratio was 1:1). 5'-Hydroperoxyspiro[chromane-2,3'-[1,2]dioxolane] (77, yield 18%) and (3S,5S)-3,5-dihydroperoxy-3-(3-phenylpropyl)-1,2-dioxolane (79, yield 22%) (Scheme 23) were synthesized in

Reactions of salicylaldehyde and enolates or their equivalents: versatile synthetic routes to chromane derivatives

• Ishmael B. Masesane and
• Zelalem Yibralign Desta

Beilstein J. Org. Chem. 2012, 8, 2166–2175, doi:10.3762/bjoc.8.244

• Ishmael B. Masesane Zelalem Yibralign Desta Department of Chemistry, University of Botswana, Private Bag 00704, Gaborone, Botswana 10.3762/bjoc.8.244 Abstract The reported methodologies for the synthesis of chromane derivatives through the reaction of salicylaldehyde and enolates are discussed

• . The enolates and their equivalents involved in the reactions discussed in this article were derived from ketones, nitroalkanes, malononitrile and α,β-unsaturated compounds. Keywords: acetophenone; chromane; enolates; malononitrile; Michael addition; salicylaldehyde; Introduction The chromane

• skeleton is found in a myriad of medicinally important compounds that have a broad range of biological activities [1][2][3][4][5][6][7]. Consequently, the synthesis of chromane derivatives has attracted the attention of synthetic chemists over the years [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15

A review of new developments in the Friedel–Crafts alkylation – From green chemistry to asymmetric catalysis

• Magnus Rueping and
• Boris J. Nachtsheim

Beilstein J. Org. Chem. 2010, 6, No. 6, doi:10.3762/bjoc.6.6

• 54b did not give the corresponding alkylated cresol 59. Instead the chromane 60 was observed in 28% yield (Scheme 25). This reaction has recently been improved and extended by applying MoCl(CO)3Cp and [Mo(CO)3Cp]2 as transition-metal catalysts [76]. A very similar FC allylation/hydroaralyation