Synthetic strategies for the preparation of γ-phostams: 1,2-azaphospholidine 2-oxides and 1,2-azaphospholine 2-oxides

• Jiaxi Xu

Beilstein J. Org. Chem. 2022, 18, 889–915, doi:10.3762/bjoc.18.90

• -phenylphosphonamidates 240a (R’ = OEt) and diaryl-N-phenylphosphinamides 240b–d (R’ = Ar), respectively, with methyl acrylate (241) via the rhodium-catalyzed oxidative coupling and subsequent intramolecular aza-Michael addition. Methyl acrylate (241) could be replaced by various electron-deficient olefins 244, including

• ]azaphosphole 1-oxides from aryl/vinyl-N-phenylphosphonamidates and aryl-N-phenylphosphinamides with electron-withdrawing ethenes via the rhodium-catalyzed oxidative coupling and subsequent intramolecular aza-Michael addition. Synthesis of 1,3-dihydro-[1,2]azaphospholo[5,4-b]pyridine 2-oxides. Funding The

Heteroleptic metallosupramolecular aggregates/complexation for supramolecular catalysis

• Prodip Howlader and
• Michael Schmittel

Beilstein J. Org. Chem. 2022, 18, 597–630, doi:10.3762/bjoc.18.62

• metal–ligand motifs often center about iridium, ruthenium, rhodium etc. [25], the dynamic ones are constructed using copper(I), zinc(II), cadmium(II), iron(II), palladium(II), etc. as metal ions due to their more rapid ligand exchange rates [24][25][26]. The strategies to prepare inert vs dynamic

• . Transition-metal catalysts play an important role for the development of intricate pharmaceutical drugs. Although transition-metal catalysts based on rhodium, cobalt, and palladium have been intensively studied, gold catalysis has received encouraging attention only recently [67][68]. Since selectivity of

• final catalyst. In the next step, a transition-metal-ion based catalyst was prepared in situ by addition of one equiv of [Rh(acac)(CO)2], which generated the monoligated rhodium complex. Finally, catalysis was carried out at 5 bar of H2/CO (1:1) that converted the [Rh(acac)(CO)2] complex into the active

Unusual highly diastereoselective Rh(II)-catalyzed dimerization of 3-diazo-2-arylidenesuccinimides provides access to a new dibenzazulene scaffold

• Anastasia Vepreva,
• Alexander S. Bunev,
• Andrey Yu. Kudinov,
• Grigory Kantin,
• Mikhail Krasavin and
• Dmitry Dar’in

Beilstein J. Org. Chem. 2022, 18, 533–538, doi:10.3762/bjoc.18.55

• at the double bond underwent cyclization as the result of intramolecular interception of the rhodium carbene, which led to the formation of indolizine [6] or 2H-chromene [7] derivatives, respectively (Figure 1). At the same time, Rh2(esp)2-catalyzed reactions of DAS with nitriles and carbonyl

• analysis (see Supporting Information File 1). A plausible mechanism of the observed transformations of DAS (shown for 1a) is presented in Scheme 2. The initially formed rhodium carbene A undergoes 1,5-electrocyclization to form intermediate B which turns into indene C as the result of a 1,5-suprafacial

BINOL as a chiral element in mechanically interlocked molecules

• Matthias Krajnc and
• Jochen Niemeyer

Beilstein J. Org. Chem. 2022, 18, 508–523, doi:10.3762/bjoc.18.53

• unit (12, used in both enantiomeric forms) or two BINOL units (26) were used for the construction of the rotaxane. The subsequent rhodium-catalyzed polymerization gave the corresponding polymers 32 in high yields of 89–98%. Here, the BINOL-based macrocycle is localized at the ammonium functionality of

Menadione: a platform and a target to valuable compounds synthesis

• Acácio S. de Souza,
• Ruan Carlos B. Ribeiro,
• Dora C. S. Costa,
• Fernanda P. Pauli,
• David R. Pinho,
• Matheus G. de Moraes,
• Fernando de C. da Silva,
• Luana da S. M. Forezi and
• Vitor F. Ferreira

Beilstein J. Org. Chem. 2022, 18, 381–419, doi:10.3762/bjoc.18.43

• studied rhodium complexes as catalysts for the arylation and alkylation of benzo- and naphthoquinones [83]. They synthesized menadione (10) (Scheme 3) by reacting 1,4-naphthoquinone (1) with methylboronic acid in the presence of [Cp*RhCl2]2 as catalyst for 10 h, in 31% isolated yield. Later in 2019, Yang

Site-selective reactions mediated by molecular containers

• Rui Wang and
• Yang Yu

Beilstein J. Org. Chem. 2022, 18, 309–324, doi:10.3762/bjoc.18.35

• hydrogenation reaction mediated by a supramolecular catalyst was reported by Raymond, Bergman and Toste in 2019 (Figure 7) [64]. In this example, the supramolecular catalyst was prepared in situ by mixing a rhodium complex with the Ga4L612− cage host G, which had a relatively larger size with pyrene-walled

• achieved with just the rhodium catalyst, by which in contrast, the fully hydrogenated product was obtained. Other series of intermolecular comparative experiments also showed the selectivity of the hydrogenation for the sterically accessible alkene over other sites and even in the presence of inherently

• by water-soluble cavitands E and F. Site-selective hydrogenation of polyenols mediated by supramolecular encapsulated rhodium catalyst. Site-selective oxidation of steroids using cyclodextrin as the anchoring template. Site-selective oxidations of linear diterpenoids with the help of cage host A

Iridium-catalyzed hydroacylation reactions of C1-substituted oxabenzonorbornadienes with salicylaldehyde: an experimental and computational study

• Angel Ho,
• Austin Pounder,
• Krish Valluru,
• Leanne D. Chen and
• William Tam

Beilstein J. Org. Chem. 2022, 18, 251–261, doi:10.3762/bjoc.18.30

• greatly differ, as described by Allen and co-workers in their 2007 report on rhodium-catalyzed cyclodimerization reactions [59]. Moreover, desymmetrization of OBD produces more unique sites of reactivity allowing for the production of regioisomeric products. In 2019, Deng et al. described syn

• catalyzed by rhodium/diene to afford the 1,2,4-trisubstituted naphthalene framework 8 with complete regio- and stereocontrol (Scheme 1) [62][63]. In 2015, the Nishimura group reported the first iridium-catalyzed addition of salicylaldehydes 14 to bicyclic alkenes 11 (Scheme 1) [64]. Although a variety of

• independently studied the rhodium-catalyzed intermolecular hydroacylation reaction of salicylaldehydes with norbornadiene derivatives. It was found that electron-donating moieties at the C1-position were well tolerated in the hydroacylation reaction giving methyl- (15b), ethyl- (15c), and t-Bu- (15d) adducts in

Earth-abundant 3d transition metals on the rise in catalysis

• Nikolaos Kaplaneris and
• Lutz Ackermann

Beilstein J. Org. Chem. 2022, 18, 86–88, doi:10.3762/bjoc.18.8

• these indisputable advances, this approach has, thus far, predominantly relied on precious, often toxic, 4d and 5d transition metals, most prominently palladium, rhodium and iridium. In sharp contrast, the use of less expensive and less toxic Earth-abundant 3d transition metals continues to be

Iron-catalyzed domino coupling reactions of π-systems

• Austin Pounder and
• William Tam

Beilstein J. Org. Chem. 2021, 17, 2848–2893, doi:10.3762/bjoc.17.196

• products and processes that reduce or eliminate the use and generation of hazardous substances, as well as increase the atom economy of the reaction [9]. Among the transition-metal (TM) catalysts often used, the late transition metals like rhodium [10][11][12][13][14], palladium [15][16][17][18][19

Me₃Al-mediated domino nucleophilic addition/intramolecular cyclisation of 2-(2-oxo-2-phenylethyl)benzonitriles with amines; a convenient approach for the synthesis of substituted 1-aminoisoquinolines

• Krishna M. S. Adusumalli,
• Lakshmi N. S. Konidena,
• Hima B. Gandham,
• Krishnaiah Kumari,
• Krishna R. Valluru,
• Satya K. R. Nidasanametla,
• Venkateswara R. Battula and
• Hari K. Namballa

Beilstein J. Org. Chem. 2021, 17, 2765–2772, doi:10.3762/bjoc.17.186

• amidines with alkynes catalyzed by either rhodium or ruthenium [55][56][57], or a metal-catalyzed aminative cyclization of 2-alkynylbenzonitriles with secondary amines [58]. Despite the advantages associated with the aforementioned protocols such as the functional group tolerance and huge substrate scope

Recent advances in organocatalytic asymmetric aza-Michael reactions of amines and amides

• Pratibha Sharma,
• Raakhi Gupta and
• Raj K. Bansal

Beilstein J. Org. Chem. 2021, 17, 2585–2610, doi:10.3762/bjoc.17.173

• high enantioselectivities (up to 65–91%) [40]. Rajasekar et al. developed an efficient one-pot tandem rhodium(II)/chiral squaramide relay catalysis for the enantioselective construction of dihydro-β-carbolines 37 from the Michael reaction of suitably substituted indole derivatives 34 with N-sulfonyl

α-Ketol and α-iminol rearrangements in synthetic organic and biosynthetic reactions

• Scott Benz and
• Andrew S. Murkin

Beilstein J. Org. Chem. 2021, 17, 2570–2584, doi:10.3762/bjoc.17.172

• with diverse biological activities [17]. The key step first involved the rhodium carbenoid-mediated OH insertion/Claisen rearrangement following complexation of diazoester 56 and allylic alcohol 57 to produce intermediate 58 (Figure 13). Addition of BF3·OEt2 to the reaction mixture then catalyzed the α

Synthesis of phenanthridines via a novel photochemically-mediated cyclization and application to the synthesis of triphaeridine

• Songeziwe Ntsimango,
• Kennedy J. Ngwira,
• Moira L. Bode and
• Charles B. de Koning

Beilstein J. Org. Chem. 2021, 17, 2340–2347, doi:10.3762/bjoc.17.152

• ], rhodium-mediated alkyne [2 + 2 + 2] cycloaddition reactions [3], and the palladium-catalysed aerobic domino Suzuki coupling/Michael addition reaction [4]. The most attractive and common strategies to phenanthridines rely on intramolecular cyclizations of various ortho-functionalized biaryl precursors

Recent advances in the syntheses of anthracene derivatives

• Giovanni S. Baviera and
• Paulo M. Donate

Beilstein J. Org. Chem. 2021, 17, 2028–2050, doi:10.3762/bjoc.17.131

• monofunctionalized naphthyl substrates. These authors demonstrated that the rhodium-catalyzed oxidative 1:2 coupling reactions of arylboronic acids 7 with alkyne 8 occurred in the presence of a copper–air oxidant, to give the corresponding 1,2,3,4-tetrasubtituted anthracene derivatives 9a and 9b (Scheme 1) [34

• substituted anthracenes by the regioselective oxidative benzannulation of 1-adamantyl-1-naphthylamines 10 with internal alkynes 11 (Scheme 2) [35]. To the best of our knowledge, this was the first successful example of rhodium-catalyzed benzannulation reactions of N-adamantyl-1-naphthylamines. Reactions of 10

• this review can serve to guide and to inspire future advances in synthetic organic chemistry for this kind of polycyclic compounds. Examples of anthracene derivatives and their applications. Rhodium-catalyzed oxidative coupling reactions of arylboronic acids with internal alkynes. Rhodium-catalyzed

On the application of 3d metals for C–H activation toward bioactive compounds: The key step for the synthesis of silver bullets

• Renato L. Carvalho,
• Amanda S. de Miranda,
• Mateus P. Nunes,
• Roberto S. Gomes,
• Guilherme A. M. Jardim and
• Eufrânio N. da Silva Júnior

Beilstein J. Org. Chem. 2021, 17, 1849–1938, doi:10.3762/bjoc.17.126

• synthetic methodologies is the C–H bond activation process that enables a straightforward access to several important and innovative compounds [14][15][16][17][18]. In the last few years, metals such as ruthenium [19][20][21], rhodium [22][23][24], palladium [25][26][27], and iridium [28][29][30] have been

A comprehensive review of flow chemistry techniques tailored to the flavours and fragrances industries

• Guido Gambacorta,
• James S. Sharley and
• Ian R. Baxendale

Beilstein J. Org. Chem. 2021, 17, 1181–1312, doi:10.3762/bjoc.17.90

N-tert-Butanesulfinyl imines in the asymmetric synthesis of nitrogen-containing heterocycles

• Joseane A. Mendes,
• Paulo R. R. Costa,
• Miguel Yus,
• Francisco Foubelo and
• Camilla D. Buarque

Beilstein J. Org. Chem. 2021, 17, 1096–1140, doi:10.3762/bjoc.17.86

• with sodium tetraarylboronates 64 was found to proceed with high diastereoselectivity under rhodium catalysis. Reddy and co-workers applied this methodology to the synthesis of 2-substituted pyrrolidines 66 [95]. The arylation of chlorinated imine (RS)-63 was performed with 2 mol % of an air-stable

• rhodium catalyst in dioxane, in the presence of 2 equivalents of MeOH, at 65 °C, leading to compounds 65 with high diastereomeric ratio. Crude amides 65 were converted into the corresponding pyrrolidines 66 in high yield by stirring at room temperature for 1 h in presence of 2.0 equivalents of LiHMDS

Recent advances in palladium-catalysed asymmetric 1,4–additions of arylboronic acids to conjugated enones and chromones

• Jan Bartáček,
• Jan Svoboda,
• Martin Kocúrik,
• Jaroslav Pochobradský,
• Alexander Čegan,
• Miloš Sedlák and
• Jiří Váňa

Beilstein J. Org. Chem. 2021, 17, 1048–1085, doi:10.3762/bjoc.17.84

• successful transition-metal catalysts are those based on rhodium, as evidenced by the number of reports that deal with the issue. The rhodium-catalysed addition of various boronic acids to conjugated cyclic enones (the so-called Hayashi–Miyaura reaction) is a well-established method for 3-unsubstituted

• substrates as well as for 2-unsubstituted chromones [17][18][19][21][22][23][24]. On the other hand, there is only one example of the usage of a rhodium-based catalyst for the addition of arylboronic acid to 3-substituted enones. The olefino-oxazoline ligand L18 has been used for the rhodium-catalysed

• is another challenging task. Nevertheless, it should be noted at this point that in the case of rhodium complex catalysis, the asymmetric addition of phenylboronic acid to enones in continuous flow has been successful [24]. In 2021, Walhers et al. presented a theoretical study based on the Q2MM

Synthesis of β-triazolylenones via metal-free desulfonylative alkylation of N-tosyl-1,2,3-triazoles

• Soumyaranjan Pati,
• Renata G. Almeida,
• Eufrânio N. da Silva Júnior and
• Irishi N. N. Namboothiri

Beilstein J. Org. Chem. 2021, 17, 762–770, doi:10.3762/bjoc.17.66

• compounds as binucleophiles for the construction of various carbocycles, heterocycles as well as in asymmetric catalysis [44][45][46][47][48][49][50]. Our initial objective to trap the aza vinyl rhodium carbenoid using 1,3-dicarbonyl compounds to form pyrazolone was unsuccessful which instead led to the

• an easy pathway to synthesize such triazolylenones. Inspired by this result, we proceeded to optimize the reaction conditions to further improve the yield. Replacement of rhodium by copper (II) acetate slowed down the reaction with a marginal change in the yield of the product 3a (Table 1, entry 2

α,γ-Dioxygenated amides via tandem Brook rearrangement/radical oxygenation reactions and their application to syntheses of γ-lactams

• Mikhail K. Klychnikov,
• Radek Pohl,
• Ivana Císařová and
• Ullrich Jahn

Beilstein J. Org. Chem. 2021, 17, 688–704, doi:10.3762/bjoc.17.58

• trans-12b can be also easily deprotected by a rhodium-catalyzed isomerization to the corresponding N-propenyl lactam followed by osmium tetroxide-catalyzed oxidative cleavage, providing lactam trans-17 in 62% yield. Additionally, the diastereomeric mixture of lactam 12o was subjected to oxidative N–O

Synthesis of N-perfluoroalkyl-3,4-disubstituted pyrroles by rhodium-catalyzed transannulation of N-fluoroalkyl-1,2,3-triazoles with terminal alkynes

• Olga Bakhanovich,
• Viktor Khutorianskyi,
• Vladimir Motornov and
• Petr Beier

Beilstein J. Org. Chem. 2021, 17, 504–510, doi:10.3762/bjoc.17.44

• Prague, Czech Republic 10.3762/bjoc.17.44 Abstract The rhodium-catalyzed transannulation of N-perfluoroalkyl-1,2,3-triazoles with aromatic and aliphatic terminal alkynes under microwave heating conditions afforded N-perfluoroalkyl-3,4-disubstituted pyrroles (major products) and N-fluoroalkyl-2,4

• -disubstituted pyrroles (minor products). The observed selectivities in the case of the reactions with aliphatic alkynes were high. Keywords: pyrrole; transannulation; rhodium carbene; triazole; Introduction Pyrroles are known to be important structural moieties appearing in natural products, synthetic drugs

• -sulfonyl-1,2,3-triazoles (Scheme 1) [11][12][13][14][15][16][17]. We have recently reported that N-perfluoroalkyl-1,2,3-triazoles [18] undergo rhodium-catalyzed transannulation reactions leading to various nitrogen heterocycles, such as imidazoles, pyrrolones, imidazolones, oxazoles, azepines [19][20][21

Synthetic strategies of phosphonodepsipeptides

• Jiaxi Xu

Beilstein J. Org. Chem. 2021, 17, 461–484, doi:10.3762/bjoc.17.41

• penicillopepsin. Synthesis of phosphonodepsipeptides as prodrugs. Synthesis of phosphonodepsithioxopeptides 198. Synthesis of phosphonodepsipeptides. Synthesis of phosphonodepsipeptides with C-1-hydroxyalkylphosphonic acid. Synthesis of phosphonodepsipeptides with C-1-hydroxyalkylphosphonate via the rhodium

Progress in the total synthesis of inthomycins

• Bidyut Kumar Senapati

Beilstein J. Org. Chem. 2021, 17, 58–82, doi:10.3762/bjoc.17.7

• synthesis of inthomycin A ((+)-1). In the beginning, conversion of enyne 127 to the corresponding (Z,E)-dienylboronic ester 128 was investigated in the presence of rhodium(I)-catalyzed anti-selective hydroboration [72] under several conditions. Unfortunately, the yield of the desired (Z,E)-128 was found to

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

• as the phosphine-catalyzed [3 + 2] cycloaddition [17], platinum-catalyzed [3 + 2] cycloaddition [18], and Rhodium-catalyzed [3 + 2] cycloaddition [12], were invented and have been extensively used in natural product synthesis in the last decade. Many reviews focusing the method development of the all

• steps. A two-step synthesis from 108 produced 109, which was converted to (−)-ditryptophenaline (12) by using Overman’s protocol [48]. Rhodium-catalyzed [3 + 2] cycloaddition In 2014, Yang and co-workers reported an efficient rhodium-catalyzed intramolecular [3 + 2] cycloaddition of 110 to give [3.3.0

• ] and [3.4.0] bicyclic systems bearing two quaternary atoms at the bridgehead position [49]. For instance, enynol 110 was treated with 5 mol % of [RhCl(CO)2]2 and carbon monoxide to afford a [3.3.0] bicycle 111 in 87% yield (Scheme 8A). The proposed catalytic cycle of this elegant rhodium-catalyzed

Using multiple self-sorting for switching functions in discrete multicomponent systems

• Amit Ghosh and
• Michael Schmittel

Beilstein J. Org. Chem. 2020, 16, 2831–2853, doi:10.3762/bjoc.16.233

• reversibility was achieved by the addition of the rhodium porphyrin 19 that reversed the system reviving the state SelfSORT-I. Since both self-sorted states exhibited a distinct fluorescence due to the changes at the zinc porphyrin sites, luminescence was used for the selective detection of DABCO in a mixture