(Bio)isosteres of ortho- and meta-substituted benzenes

• H. Erik Diepers and
• Johannes C. L. Walker

Beilstein J. Org. Chem. 2024, 20, 859–890, doi:10.3762/bjoc.20.78

• carbene insertion into bicyclobutane was reported in 2022 by Bychek and Mykhailiuk [74]. Previously the same group had also reported the synthesis of BCPs containing a difluorinated bridge by CF2 carbene insertion into bicyclobutanes [75]. More recently Davies and co-worker reported the one-pot synthesis

• of bridge difluorinated BCPs from α-allyldiazoacetates. In their reaction sequence, intramolecular cyclopropanation first forms the bicyclobutane which is then subjected to CF2 carbene insertion to yield the BCP [76]. Another useful pathway to 1,2,3-BCPs is strain release functionalisation as was

N-Boc-α-diazo glutarimide as efficient reagent for assembling N-heterocycle-glutarimide diads via Rh(II)-catalyzed N–H insertion reaction

• Grigory Kantin,
• Pavel Golubev,
• Alexander Sapegin,
• Alexander Bunev and
• Dmitry Dar’in

Beilstein J. Org. Chem. 2023, 19, 1841–1848, doi:10.3762/bjoc.19.136

• acknowledged to be effective in introducing substituents to the nitrogen atoms of NH-heterocycles by means of carbene insertion into the N–H bond upon catalytic or photolytic decomposition of diazo compounds [25]. Furthermore, the reaction of N-heterocycles containing multiple non-equivalent nitrogen atoms

Synthetic strategies of phosphonodepsipeptides

• Jiaxi Xu

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

• dichlorophosphites followed by alcoholysis with hydroxy esters, the phosphinylation of hydroxy esters with phosphonochloridites followed by oxidation, and the carbene insertion of N-protected amino acids with 1-diazoalkylphosphonates. This review includes the synthesis of α-, β-, and γ-phosphonodepsipeptides and

• tetraacetate (Scheme 39) [60][61]. To develop novel bone-targeting prodrugs, a copper-catalyzed carbene insertion of tetraethyl diazomethyldiphosphonate (216) with N-Boc-protected amino acids 214 and 215 provided a simple method to synthesize phosphonodepsipeptides 217 and 218 containing a C-1

• -hydroxyalkylphosphonate motif in good yields (Scheme 40) [62]. The transition metal-catalyzed carbene insertion of 1-diazoalkylphononates and N-protected amino acids is an efficient and convenient method for the synthesis of phosphonodepsipeptides with C-1-hydroxyalkylphosphonic acids because the required 1

Preparation and in situ use of unstable N-alkyl α-diazo-γ-butyrolactams in Rh^II-catalyzed X–H insertion reactions

• Maria Eremeyeva,
• Daniil Zhukovsky,
• Dmitry Dar’in and
• Mikhail Krasavin

Beilstein J. Org. Chem. 2020, 16, 607–610, doi:10.3762/bjoc.16.55

• formation, in various RhII-catalyzed X–H insertion reactions, particularly the recently described rhodium carbene insertion into O–H [1], N–H [2] and S–H [3] bonds of alcohols, aromatic amines, and thiols, respectively. Herein, we report the results of these studies. Results and Discussion Three N-alkyl-α

One hundred years of benzotropone chemistry

• Arif Dastan,
• Haydar Kilic and
• Nurullah Saracoglu

Beilstein J. Org. Chem. 2018, 14, 1120–1180, doi:10.3762/bjoc.14.98

CF₃SO₂X (X = Na, Cl) as reagents for trifluoromethylation, trifluoromethylsulfenyl-, -sulfinyl- and -sulfonylation. Part 1: Use of CF₃SO₂Na

• Hélène Guyon,
• Hélène Chachignon and
• Dominique Cahard

Beilstein J. Org. Chem. 2017, 13, 2764–2799, doi:10.3762/bjoc.13.272

Enantioselective carbenoid insertion into C(sp³)–H bonds

• J. V. Santiago and
• A. H. L. Machado

Beilstein J. Org. Chem. 2016, 12, 882–902, doi:10.3762/bjoc.12.87

• formation rate by direct decomposition of the precursors 42a and 42b. The competition between carbene insertion and chiral carbenoid insertion into C(sp3)–H bonds decreases the enantioselectivity of this transformation. To confirm the copper carbenoid formation and its participation on the insertion

Recent advances in C(sp³)–H bond functionalization via metal–carbene insertions

• Bo Wang,
• Di Qiu,
• Yan Zhang and
• Jianbo Wang

Beilstein J. Org. Chem. 2016, 12, 796–804, doi:10.3762/bjoc.12.78

• simple aliphatic C(sp3)–H bonds. In this context, catalytic metal–carbene C(sp3)–H bond insertion represents an alternative and unique approach for this purpose. Metal–carbene insertion into a C(sp3)–H bond, well-recognized as one of the typical reactions of carbene species, have been studied extensively

• intramolecular reaction systems, or with relatively active C–H bonds, such as allylic, benzylic or the C–H bonds adjacent to the oxygen or nitrogen, the corresponding site-selective metal–carbene insertion into simple aliphatic C(sp3)–H bonds has also been challenged in intermolecular reaction systems and one

• secondary C–H bonds, even the secondary benzylic C–H bonds (Scheme 2). Notably, for the site-selectivity of carbene insertion into primary, secondary and tertiary C–H bonds, the electronic and steric factors operate in the opposite directions. It is thus possible to tune or even revise the selectivity by

Gold-catalyzed direct alkynylation of tryptophan in peptides using TIPS-EBX

• Gergely L. Tolnai,
• Jonathan P. Brand and
• Jerome Waser

Beilstein J. Org. Chem. 2016, 12, 745–749, doi:10.3762/bjoc.12.74

• . It has been achieved in the past for example by Francis and co-workers and Ball and co-workers using rhodium-catalyzed carbene-insertion reactions [21][22][23] or via direct C–H arylation [24][25][26][27][28][29]. If the installation of alkynes on peptides or proteins is desired, an indirect method

Recent applications of ring-rearrangement metathesis in organic synthesis

• Sambasivarao Kotha,
• Milind Meshram,
• Priti Khedkar,
• Shaibal Banerjee and
• Deepak Deodhar

Beilstein J. Org. Chem. 2015, 11, 1833–1864, doi:10.3762/bjoc.11.199

• with the aid of a carbene insertion reaction. Further, this cyclopropene system 16 was subjected to RRM in the presence of catalyst 1 to generate 3-pyrroline derivatives 18a,b using simple starting materials in a single step (Scheme 1). A wide range of heterocycles have been assembled by RRM. When a

Rh(III)-catalyzed directed C–H bond amidation of ferrocenes with isocyanates

• Satoshi Takebayashi,
• Tsubasa Shizuno,
• Takashi Otani and
• Takanori Shibata

Beilstein J. Org. Chem. 2012, 8, 1844–1848, doi:10.3762/bjoc.8.212

• reported to date, and there is only one report of enantioselective C–H activation of ferrocenes [6][7][8][9]. Schmalz et al. reported the first catalytic C–H activation of ferrocenes using a Cu-catalyzed intramolecular carbene insertion into a Cp–H bond [6]. Further, they showed that the reaction could be

Gold-catalyzed naphthalene functionalization

• Pedro J. Pérez,
• M. Mar Díaz-Requejo and
• Iván Rivilla

Beilstein J. Org. Chem. 2011, 7, 653–657, doi:10.3762/bjoc.7.77

• bond. In addition, no byproducts derived from carbene coupling were observed. Keywords: carbene insertion; copper catalysts; diazoacetates; gold catalysts; naphthalene functionalization; selective insertion; Introduction At the end of the nineteenth century, Buchner discovered [1] the thermal and

• complexes IPrMCl (M = Cu, Au) catalyze the transfer of carbene groups C(R)CO2Et (R = H, Me) to naphthalene, in the presence of NaBAr'4 as halide scavenger, to give mixtures of products via carbene insertion into a C–H bond or by addition to a double bond. In the case of copper, norcaradiene type compounds

Mitomycins syntheses: a recent update

• Jean-Christophe Andrez

Beilstein J. Org. Chem. 2009, 5, No. 33, doi:10.3762/bjoc.5.33

• tributyltin fluoride [112]. After protecting group manipulations and formation of the diazoester 138 with p-nitrobenzenesulfonylazide (PNBSA), the key carbene insertion was achieved using copper(I) in the presence of bis-oxazoline 139. A 9:1 ratio of 141 and 142 was obtained after direct chloranil oxidation

• the dihydroxylation. Compounds 134a and 134b could be tailored as mitomycin A and mitomycin B derivatives respectively but issues pertaining to the introductions of the C9a oxygenated functionality and the carbamoyl moiety at C10 remain unsolved. 5.3. Sulikowski. Buchwald coupling and carbene

• insertion The laboratory of G.A. Sulikowski proposed a synthesis of 1,2-aziridinomitosenes [106][107] using as key transformations a Buchwald–Hartwig cross-coupling [108][109][110] and a chemoselective intramolecular carbon-hydrogen metal-carbenoid insertion reaction (Scheme 39). The chiral pyrolidine 136