Cofactor-independent C–C bond cleavage reactions catalyzed by the AlpJ family of oxygenases in atypical angucycline biosynthesis

• Jinmin Gao,
• Liyuan Li,
• Shijie Shen,
• Guomin Ai,
• Bin Wang,
• Fang Guo,
• Tongjian Yang,
• Hui Han,
• Zhengren Xu,
• Guohui Pan and
• Keqiang Fan

Beilstein J. Org. Chem. 2024, 20, 1198–1206, doi:10.3762/bjoc.20.102

• cofactor-independent manner. Keywords: angucyclines; aromatic polyketide; biosynthesis; cofactor-independent oxygenase; oxidative rearrangement reaction; Introduction The angucyclines represent a large class of natural products biosynthesized by type II polyketide synthases. Within this category, a

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

• should be noted that the three-step strategy (dithiolane protection, oxidative rearrangement, and hydrodesulfurization) can be used to treat carbonyl functional groups as synthetic equivalents of cis-alkenes (Scheme 10c), as is shown by the highly stereoselective conversion of α-phenylacetophenone (60

Total synthesis of grayanane natural products

• Nicolas Fay,
• Rémi Blieck,
• Cyrille Kouklovsky and
• Aurélien de la Torre

Beilstein J. Org. Chem. 2022, 18, 1707–1719, doi:10.3762/bjoc.18.181

• , olefin, ketone or epoxide functionalities. From a biosynthetic point of view, grayananes arise from an oxidative rearrangement of the ent-kaurane skeleton (Scheme 1). The diversity is generated by cytochromes P450 (CYP) enzymatic oxidation of the grayanane skeleton [17]. The biological activities and low

All-carbon [3 + 2] cycloaddition in natural product synthesis

• Zhuo Wang and
• Junyang Liu

Beilstein J. Org. Chem. 2020, 16, 3015–3031, doi:10.3762/bjoc.16.251

• tetracyclic compound 56. Dihydroxylation of freshly prepared 56 with OsO4 and then selective tosylation afforded 57 in 39% yield over two steps. Exposure of 57 to DBU upon heating gave the elimination product 58, which was subjected to an oxidative rearrangement with PDC to give enone 59 in 68% yield. Copper

Recent advances in hypervalent iodine(III)-catalyzed functionalization of alkenes

• Xiang Li,
• Pinhong Chen and
• Guosheng Liu

Beilstein J. Org. Chem. 2018, 14, 1813–1825, doi:10.3762/bjoc.14.154

• products. Recently, Jacobsen and co-workers reported a highly enantioselective gem-difluorination of various cinnamic acid derivatives through the same oxidative rearrangement (Scheme 16) [68]. During the catalysts screening, they found that the benzylic unit in the catalysts was essential for a high

• first a nucleophilic attack from the vinylogous ester, then by the aromatic group, providing the final outcomes. Wirth and co-workers developed an oxidative rearrangement of alkenes to chiral α-aryl ketones, in which electron-deficient chiral lactic acid-based hypervalent iodine reagents were

• dramatically decreased yield and enantioselectivity (Scheme 18). Similar oxidative rearrangement reactions with haloalkenes generated α-halo ketones [73]. NBS also oxidizes iodoarene 65 to form the brominating agent 66 [74]. Braddock and co-workers reported an organocatalyzed transformation of electrophilic

A survey of chiral hypervalent iodine reagents in asymmetric synthesis

• Soumen Ghosh,
• Suman Pradhan and
• Indranil Chatterjee

Beilstein J. Org. Chem. 2018, 14, 1244–1262, doi:10.3762/bjoc.14.107

• displacement of the aryl iodide by the CO2R group in 77 leading to chiral lactones of type 78 [56]. Rearrangement strategy Wirth et al. used I(III) reagent 8b for the development of a stereoselective oxidative rearrangement method to synthesize α-arylated carbonyls 81 from α,β-unsaturated carbonyls 80 (Scheme

•  16, upper part) [57][58]. The reaction proceeds via the formation of the phenyliodinate intermediate 82 followed by a stereoselective 1,2-aryl migration. Elegantly, they utilized the 1,2-aryl migration approach to develop an enantioselective oxidative rearrangement of 1,1-disubstituted olefins 83

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

Biosynthesis of oxygen and nitrogen-containing heterocycles in polyketides

• Franziska Hemmerling and
• Frank Hahn

Beilstein J. Org. Chem. 2016, 12, 1512–1550, doi:10.3762/bjoc.12.148

• capable of catalysing the later conversion of versiconal (105) to versicolorin B (106) [88]. Averufin (102) is the starting point for the first oxidative rearrangement. Feeding experiments with isotope-labelled averufins (102) showed that their C5’ and C6’-carbons (pink) are excised on the way to

The synthesis of active pharmaceutical ingredients (APIs) using continuous flow chemistry

• Marcus Baumann and
• Ian R. Baxendale

Beilstein J. Org. Chem. 2015, 11, 1194–1219, doi:10.3762/bjoc.11.134

• worked well. As seen above, avoiding detrimental exotherms in scale up campaigns is a common reason for developing a continuous flow process. This approach is also demonstrated in the synthesis of the pyrrolotriazinone 73 via a exothermic oxidative rearrangement from 75, a key intermediate towards

A facile synthesis of functionalized 7,8-diaza[5]helicenes through an oxidative ring-closure of 1,1’-binaphthalene-2,2’-diamines (BINAMs)

• Youhei Takeda,
• Masato Okazaki,
• Yoshiaki Maruoka and
• Satoshi Minakata

Beilstein J. Org. Chem. 2015, 11, 9–15, doi:10.3762/bjoc.11.2

• develop oxidative transformations of aromatic amines for the construction of diverse aza-containing π-conjugated functional molecules [27][28][29][30], we have recently discovered an iodine-containing oxidant-induced unusual oxidative rearrangement of BINAMs leading exclusively to U-shaped azaacenes

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

• a similar way starting from 2-allyl-2-hydroperoxychromane (76) and (4,4-dihydroperoxyhept-6-enyl)benzene (78), respectively [254]. An oxidative rearrangement takes place in the reaction of azepino[4,5-b]indole 80 with ozone. The addition of ozone to the endocyclic double bond (molozonide 81) and the

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

• -methylenetetrahydrofurans, a brief survey of their reactivity was performed. Several reactions involving the vinyl chloride function proved unsuccessful [28][29]. Attempts to perform oxidative rearrangement and dehydration failed and functionalisation of the hydroxy group appeared difficult [30][31]. Initially, the adduct

Oxidative allylic rearrangement of cycloalkenols: Formal total synthesis of enantiomerically pure trisporic acid B

• Silke Dubberke,
• Muhammad Abbas and
• Bernhard Westermann

Beilstein J. Org. Chem. 2011, 7, 421–425, doi:10.3762/bjoc.7.54

• resolution; natural products; oxidative rearrangement; pig liver esterase (PLE); trisporic acid B; Introduction The generation of chiral, non-racemic compounds bearing a stereogenic quaternary carbon centre is of great interest [1][2][3][4][5][6][7][8]. Therefore, much effort has been directed towards the