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

• initiated, the reaction will propagate, which typically involves the insertion of a π-system (carbometallation of alkenes/alkynes) in the case of organoiron species (Scheme 2). Alternatively, the generated radical species may undergo radical addition to alkenes, alkynes, or aromatic arenes. The final step

• Echeverria demonstrated a mechanistically distinct protocol for the synthesis of 1,3-dienes 36 (Scheme 7) [72]. Compared to previous Fe-catalyzed carbomagnesiation reactions (Scheme 6) where carbometallation occurs in a concerted syn-manner this protocol, instead, is initiated by the oxidative cyclization of

• borylmetallation across the alkene in a syn-fashion 58. Side-on coordination of the haloalkene’s π-bond can trigger a syn-carbometallation 59. A base-mediated 1,2- elimination will deliver the alkenylboration product as well as regenerate 56. The methodology was applied towards the synthesis of (±)-imperanene

Coupling of α,α-difluoro-substituted organozinc reagents with 1-bromoalkynes

• Artem A. Zemtsov,
• Alexander D. Volodin,
• Vitalij V. Levin,
• Marina I. Struchkova and
• Alexander D. Dilman

Beilstein J. Org. Chem. 2015, 11, 2145–2149, doi:10.3762/bjoc.11.231

• interacts with bromoalkyne 3 either by oxidative addition generating copper(III) intermediate 6 or by triple bond carbometallation [38] generating copper(I) intermediate 7. Subsequent reductive elimination (from 6) or β-elimination (from 7) leads to the product and regenerates the copper(I) catalyst

Intramolecular carbonickelation of alkenes

• Rudy Lhermet,
• Muriel Durandetti and
• Jacques Maddaluno

Beilstein J. Org. Chem. 2013, 9, 710–716, doi:10.3762/bjoc.9.81

• skeleton was achieved by using NiBr2bipy catalysis. Keywords: alkenes; carbometallation; carbonickelation; cyclization; Heck-type reaction; nickel catalysis; Introduction Carbometalation is a reaction involving the addition of an organometallic species to a nonactivated alkene or alkyne to form a new

Carbolithiation of N-alkenyl ureas and N-alkenyl carbamates

• Julien Lefranc,
• Alberto Minassi and
• Jonathan Clayden

Beilstein J. Org. Chem. 2013, 9, 628–632, doi:10.3762/bjoc.9.70

• products that may be deprotected in situ to provide a new connective route to hindered amines. Keywords: carbamate; carbolithiation; carbometallation; organolithium; stereospecificity; styrene; urea; Introduction Enamines and N-acyl enamines are in general nucleophiles, reacting with electrophiles at the

Intramolecular carbolithiation cascades as a route to a highly strained carbocyclic framework: competition between 5-exo-trig ring closure and proton transfer

• William F. Bailey and
• Justin D. Fair

Beilstein J. Org. Chem. 2013, 9, 537–543, doi:10.3762/bjoc.9.59

• temperature. Keywords: carbolithiation cascade; carbometallation; intramolecular carbolithiation; intermolecular proton transfer; lithium–halogen exchange; strained hydrocarbons; Introduction The first publication describing an intramolecular carbolithiation appeared in 1968: Drozd and co-workers reported

Regio- and stereoselective carbometallation reactions of N-alkynylamides and sulfonamides

• Yury Minko,
• Morgane Pasco,
• Helena Chechik and
• Ilan Marek

Beilstein J. Org. Chem. 2013, 9, 526–532, doi:10.3762/bjoc.9.57

• species geminated to the amide moiety. The latter species are involved in numerous synthetically useful transformations leading to valuable building blocks in organic synthesis. Here we describe in full the results of our studies related to the carbometallation reactions of N-alkynylamides. Keywords

• : carbometallation; enamides; organocopper; regiochemistry; ynamides; Introduction Due to a strong differentiation of electron density on the two sp-hybridized carbon atoms, N-alkynylamides (ynamides) have become attractive substrates involved in many synthetically useful transformations [1][2][3][4]. The

• alkenes is the carbometallation reaction of alkynes [16][17][18], ynamide should be a suitable substrate for the regio- and stereoselective synthesis of enamide through carbometallation reaction [19][20][21][22]. Although the stereoselectivity of the carbocupration is usually controlled through a syn

Inter- and intramolecular enantioselective carbolithiation reactions

• Asier Gómez-SanJuan,
• Nuria Sotomayor and
• Esther Lete

Beilstein J. Org. Chem. 2013, 9, 313–322, doi:10.3762/bjoc.9.36

• the possibility of introducing further functionalization on the molecule by trapping the reactive organolithium intermediates with electrophiles. Keywords: alkenes; asymmetric synthesis; carbolithiation; carbometallation; enantioselectivity; lithium; Introduction The carbolithiation reaction has

Radical zinc-atom-transfer-based carbozincation of haloalkynes with dialkylzincs

• Fabrice Chemla,
• Florian Dulong,
• Franck Ferreira and
• Alejandro Pérez-Luna

Beilstein J. Org. Chem. 2013, 9, 236–245, doi:10.3762/bjoc.9.28

• a formal anti-selective carbozincation reaction. Upon warming, the zinc carbenoid is stereochemically labile and isomerizes to its more stable form. Keywords: carbenoids; carbometallation; carbozincation; radicals; tandem reaction; Introduction The last few years have witnessed a gaining interest

• alkyl iodides in the presence of Me2Zn/O2 with β-(propargyloxy)enoates entails the intramolecular carbometallation of the pendant alkynes substituted by silyl, alkyl, aryl, alkenyl or amino groups by a 5-exo dig radical cyclization step [37][38]. Intermolecular carbozincation of terminal arylacetylenes

• (Scheme 4). Moreover, if 13 is indeed formed, it would also lead to alkyne 10 following Fritsch–Buttenberg–Wieschell (FBW) rearrangement [55][56][57]. Since the presence of the oxygen atom in the propargylic position should facilitate the carbometallation reaction [58], this mechanistic pathway provides a

Carbometallation chemistry

• Ilan Marek

Beilstein J. Org. Chem. 2013, 9, 234–235, doi:10.3762/bjoc.9.27

• Ilan Marek Schulich Faculty of Chemistry, Technion-Israel Institute of Technology, Haifa 32000, Israel 10.3762/bjoc.9.27 Keywords: carbometallation; Following the pioneering Ziegler addition of nucleophiles to nonactivated unsaturated carbon–carbon bonds, the controlled carbometallation reaction

• carbometallation reactions. In the past few decades, the intra- as well as intermolecular additions of various organometallic species to a large variety of alkynes, alkenes and allenes have been successfully reported. Although the carbometallation reaction on alkynes is generally a well-controlled and predictable

• will find excellent contributions tackling various problems of carbometallation reactions, indicating a lively and rapidly moving field, and I have no doubt that more elegant transformations of C–C unsaturated bonds will continue to appear, including the enantioselective carbometallation reaction of

Intramolecular carbolithiation of N-allyl-ynamides: an efficient entry to 1,4-dihydropyridines and pyridines – application to a formal synthesis of sarizotan

• Wafa Gati,
• Mohamed M. Rammah,
• Mohamed B. Rammah and
• Gwilherm Evano

Beilstein J. Org. Chem. 2012, 8, 2214–2222, doi:10.3762/bjoc.8.250

• formal synthesis of the anti-dyskinesia agent sarizotan, further extends the use of ynamides in organic synthesis and further demonstrates the synthetic efficiency of carbometallation reactions. Keywords: carbolithiation; carbometallation; dihydropyridines; organolithium reagents; pyridines; sarizotan

• ; ynamides; Introduction Since the discovery of the carbometallation reaction by Ziegler and Bähr in 1928 [1], this reaction has evolved as a most powerful tool to construct carbon–carbon bonds. An ever increasing number of organometallic species have been shown over the years to be suitable reagents for

• the carbometallation of various carbon–carbon multiple bonds. Lithium, copper, zinc, magnesium, zirconium, titanium, palladium and other metals are suitable for this transformation and considerable progress has recently been made in this area. Among these systems, the carbometallation of alkynes

Highly stereocontrolled synthesis of trans-enediynes via carbocupration of fluoroalkylated diynes

• Tsutomu Konno,
• Misato Kishi and
• Takashi Ishihara

Beilstein J. Org. Chem. 2012, 8, 2207–2213, doi:10.3762/bjoc.8.249

• ; carbometallation; diyne; enediyne; fluorine; highly regioselective; highly stereoselective; Introduction trans-Enediynes (trans-hex-3-ene-1,5-diynes), as shown in Figure 1, are well-recognized as one of the most important building blocks because they are frequently utilized for the synthesis of π-conjugated