Hypervalent iodine-catalyzed amide and alkene coupling enabled by lithium salt activation

• Akanksha Chhikara,
• Fan Wu,
• Navdeep Kaur,
• Prabagar Baskaran,
• Alex M. Nguyen,
• Zhichang Yin,
• Anthony H. Pham and
• Wei Li

Beilstein J. Org. Chem. 2024, 20, 1405–1411, doi:10.3762/bjoc.20.122

• .20.122 Abstract Hypervalent iodine catalysis has been widely utilized in olefin functionalization reactions. Intermolecularly, the regioselective addition of two distinct nucleophiles across the olefin is a challenging process in hypervalent iodine catalysis. We introduce here a unique strategy using

SOMOphilic alkyne vs radical-polar crossover approaches: The full story of the azido-alkynylation of alkenes

• Julien Borrel and
• Jerome Waser

Beilstein J. Org. Chem. 2024, 20, 701–713, doi:10.3762/bjoc.20.64

• , greatly increasing the molecular complexity of the starting substrate. Using radical chemistry would lead to a regioselective addition of azide radicals to the alkene, forming selectively the most stabilized C-centered radical. A prominent method for the generation of azide radicals relies on hypervalent

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

• an Fe(II) species and S2O82−, a cascade of SET reactions between the alkylcarbazate and the Fe catalyst will lead to the formation of the alkoxycarbonyl 125. Regioselective addition of the radical across the electron-neutral olefin will generate the radical intermediate 126, followed by the 6-endo

Advances in mercury(II)-salt-mediated cyclization reactions of unsaturated bonds

• Sumana Mandal,
• Raju D. Chaudhari and
• Goutam Biswas

Beilstein J. Org. Chem. 2021, 17, 2348–2376, doi:10.3762/bjoc.17.153

• enol ether derivative 79 forming carbocyclic compounds 81 with good yields via intermediate 80 [78]. The cyclization of compounds 79 undergo regioselective addition with the triple bond in exocyclic alkene position leading to the formation of α-mercury ketone 80, which were later functionalized by

A recent overview on the synthesis of 1,4,5-trisubstituted 1,2,3-triazoles

• Pezhman Shiri,
• Ali Mohammad Amani and
• Thomas Mayer-Gall

Beilstein J. Org. Chem. 2021, 17, 1600–1628, doi:10.3762/bjoc.17.114

• compounds 25 through the regioselective addition and cyclization reaction of 1,1-enediamines (EDAMs) 24 with p-methylbenzenesulfonyl azide in 1,4-dioxane as solvent at reflux was presented by Yan et al. Some substituted EDAMs (R1 = R2) were concluded to be treated with TsN3. In continuation, substituted

• -triazoles 19 containing a sulfur-based side chain. Synthesis of fully decorated 1,2,3-triazole compounds 25 through the regioselective addition and cyclization reaction of EDAMs 24 with p-methylbenzenesulfonyl azide. A reasonable mechanism for the synthesis of fully decorated 1,2,3-triazole compounds 25

• through the regioselective addition and cyclization reaction of EDAMs 24 with p-methylbenzenesulfonyl azide. Synthesis of 1,4,5-trisubstituted glycosyl-containing 1,2,3-triazole derivatives 30 from the reaction of glycosyl azides 28 with enolates of active

Regioselective addition of Grignard reagents to N-acylpyrazinium salts: synthesis of substituted 1,2-dihydropyrazines and Δ⁵-2-oxopiperazines

• Valentine R. St. Hilaire,
• William E. Hopkins,
• Yenteeo S. Miller,
• Srinivasa R. Dandepally and
• Alfred L. Williams

Beilstein J. Org. Chem. 2019, 15, 72–78, doi:10.3762/bjoc.15.8

• , North Carolina Central University, Durham, North Carolina 27707, United States 10.3762/bjoc.15.8 Abstract The regioselective addition of Grignard reagents to mono- and disubstituted N-acylpyrazinium salts affording substituted 1,2-dihydropyrazines in modest to excellent yields (45–100%) is described

• . Under acidic conditions, these 1,2-dihydropyrazines can be converted to substituted Δ5-2-oxopiperazines providing a simple and efficient approach towards their preparation. Keywords: N-acylpyrazinium salts; 1,2-dihydropyrazines; Grignard reagents; Δ5-2-oxopiperazines; regioselective addition

• adding to 2-cyano-6-morpholinylpyrazine [21]. As a part of our continued exploration into the synthetic utility of N-acylpyrazinium salts, herein we report the regioselective addition of Grignard reagents to mono- and disubstituted N-acylpyrazinium salts towards the synthesis of 1,2-dihydropyrazines and

Cobalt-catalyzed nucleophilic addition of the allylic C(sp³)–H bond of simple alkenes to ketones

• Tsuyoshi Mita,
• Masashi Uchiyama,
• Kenichi Michigami and
• Yoshihiro Sato

Beilstein J. Org. Chem. 2018, 14, 2012–2017, doi:10.3762/bjoc.14.176

• Tsuyoshi Mita Masashi Uchiyama Kenichi Michigami Yoshihiro Sato Faculty of Pharmaceutical Sciences, Hokkaido University, Sapporo 060-0812, Japan 10.3762/bjoc.14.176 Abstract We herein describe a cobalt/Xantphos-catalyzed regioselective addition of simple alkenes to acetophenone derivatives

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

• radical [ArN(CO2Me)O•] 33, would lead to two regioisomeric oxytrifluoromethylated products. Fortunately, this issue was solved by the primary formation of the CF3 radical and thus a regioselective addition. After optimization of the reaction conditions with styrene as model alkene, the method was applied

Silica: An efficient catalyst for one-pot regioselective synthesis of dithioethers

• Samir Kundu,
• Babli Roy and
• Basudeb Basu

Beilstein J. Org. Chem. 2014, 10, 26–33, doi:10.3762/bjoc.10.5

• afforded allyl(phenyl)sulfane in excellent yield. Since alkenes are also known to undergo ‘click’ addition with thiols [39][40], excess use of thiols could effectively produce dithioethers, and based on a regioselective addition one could achieve either vicinal or 1,3-dithioethers in one-pot consecutive

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

• performed (Table 3, entry 6), results were very similar to those from the addition of copper or cuprate reagents (Table 3, entries 1 and 5, respectively). Thus, the best compromise we found for the regioselective addition of a methyl group on ynamides 7a and 7b was through the addition of a cuprate

• carbocupration reaction is again at the center of interest but this time for the regioselective addition of organocopper derivatives to various ynamide species. Particularly interesting is the carbocupration of N-alkynyl carbamates 7, bearing Evans’s oxazolidinone chiral auxiliary, which leads to the formation

When cyclopropenes meet gold catalysts

• Frédéric Miege,
• Christophe Meyer and
• Janine Cossy

Beilstein J. Org. Chem. 2011, 7, 717–734, doi:10.3762/bjoc.7.82

• %) was not as high as with Gagosz’s catalyst (83%). Lee and Hadfield took advantage of these findings to develop the regioselective addition of alcohols (used in excess) to allenes such as 14 catalyzed by [(IPr)AuOTf] (10 mol %) to produce the tert-allylic ethers 15 as the kinetic products (Scheme 8) [29