Synthesis of 2-oxindoles via 'transition-metal-free' intramolecular dehydrogenative coupling (IDC) of sp² C–H and sp³ C–H bonds

• Nivesh Kumar,
• Santanu Ghosh,
• Subhajit Bhunia and
• Alakesh Bisai

Beilstein J. Org. Chem. 2016, 12, 1153–1169, doi:10.3762/bjoc.12.111

• -carbon quaternary center at the pseudo benzylic position has been achieved via a ‘transition-metal-free’ intramolecular dehydrogenative coupling (IDC). The construction of 2-oxindole moieties was carried out through formation of carbon–carbon bonds using KOt-Bu-catalyzed one pot C-alkylation of β-N

• -arylamido esters with alkyl halides followed by a dehydrogenative coupling. Experimental evidences indicated toward a radical-mediated path for this reaction. Keywords: C−H functionalization; intramolecular dehydrogenative coupling (IDC); iodine; N-iodosuccinimide; oxidants; 2-oxindoles; Introduction The

• oxidative coupling of two C–H bonds [also termed as cross-dehydrogenative-coupling (CDC)] in the formation of C–C bonds [11][12][13][14][15][16]. This was facilitated by the introduction of transition metals in organic synthesis providing an amazing tool to explore these oxidative coupling reactions in an

Cascade alkylarylation of substituted N-allylbenzamides for the construction of dihydroisoquinolin-1(2H)-ones and isoquinoline-1,3(2H,4H)-diones

• Ping Qian,
• Bingnan Du,
• Wei Jiao,
• Haibo Mei,
• Jianlin Han and
• Yi Pan

Beilstein J. Org. Chem. 2016, 12, 301–308, doi:10.3762/bjoc.12.32

• cross-dehydrogenative coupling (CDC) reactions of alkanes, which were reported by Li and other groups [11][12][13][14][15]. Recently, several types of reactions with alkanes as substrates have been developed, such as the Minisci reaction with heteroarenes [16][17], radical addition to unsaturated bonds

Enantioselective additions of copper acetylides to cyclic iminium and oxocarbenium ions

• Jixin Liu,
• Srimoyee Dasgupta and
• Mary P. Watson

Beilstein J. Org. Chem. 2015, 11, 2696–2706, doi:10.3762/bjoc.11.290

• for enantioselective alkynylations of cyclic electrophiles. The first enantioselective, copper-catalyzed alkynylation of a cyclic iminium ion was reported by Li’s research group in 2004 [22]. Building on their development of a cross-dehydrogenative coupling (CDC) reaction between benzylic amines and

Pd(OAc)₂-catalyzed dehydrogenative C–H activation: An expedient synthesis of uracil-annulated β-carbolinones

• Biplab Mondal,
• Somjit Hazra,
• Tarun K. Panda and
• Brindaban Roy

Beilstein J. Org. Chem. 2015, 11, 1360–1366, doi:10.3762/bjoc.11.146

• rich indole C3–H bond for the synthesis of uracil annulated β-carbolinones [54][55][56]. Herein, we report our novel approach towards the synthesis of uracil annulated β-carbolinones via an intramolecular dehydrogenative coupling reaction of indole-2-carboxamides. Results and Discussion We started our

• point for catalyst screening. The amide 4a (R1 = R2 = R3 = R4 = Me) was used as a model substrate for this dehydrogenative coupling reaction. The reaction was set up in the presence of Pd(OAc)2 (10 mol %), Cu(OAc)2 (2 equiv) in DMF under open air at 70 °C (Table 1, entry 1). After 8 h we obtained 35

• the eluent to afford product 5. For details see Supporting Information File 1. Naturally occurring β-carbolinones. ORTEP diagram of 5h. Preparation of starting substrate. Synthesis of various β-carbolinone derivatives. Proposed mechanistic pathway. Optimization of intramolecular dehydrogenative

Cross-dehydrogenative coupling for the intermolecular C–O bond formation

• Igor B. Krylov,
• Vera A. Vil’ and
• Alexander O. Terent’ev

Beilstein J. Org. Chem. 2015, 11, 92–146, doi:10.3762/bjoc.11.13

• -dehydrogenative C–O coupling reaction are dictated mainly by the nature of the C-reagent. Hence, in the present review the data are classified according to the structures of C-reagents, and, in the second place, according to the type of oxidative systems. Besides the typical cross-dehydrogenative coupling

• ; C–H functionalization; C–O bond formation; cross-dehydrogenative coupling; oxidative cross-coupling; Introduction The development of methods for the cross-dehydrogenative coupling (CDC; or oxidative cross coupling) is an important field of modern organic chemistry. These terms commonly refer to

• -dehydrogenative coupling can be employed to form a new bond with high atomic efficiency and does not require additional synthetic steps for the introduction of functional groups (for example, such as -Hal, -OTf, -BR2, -SnR3, -SiR3, -ZnHal, -MgHal) into molecules necessary in other cross-coupling reactions

Sequential decarboxylative azide–alkyne cycloaddition and dehydrogenative coupling reactions: one-pot synthesis of polycyclic fused triazoles

• Kuppusamy Bharathimohan,
• Thanasekaran Ponpandian,
• A. Jafar Ahamed and
• Nattamai Bhuvanesh

Beilstein J. Org. Chem. 2014, 10, 3031–3037, doi:10.3762/bjoc.10.321

• methodology is more convenient to produce the complex polycyclic molecules in a simple way. Keywords: copper(II) acetate; decarboxylative CuAAC; dehydrogenative coupling; fused triazoles; one-pot synthesis; Introduction The copper-catalyzed Huisgen [3 + 2] cycloaddition (or copper-catalyzed azide–alkyne

• were developed for the synthesis of fused triazoles [40]. Ackermann referred to an intramolecular dehydrogenative coupling of 1,4-disubstituted triazoles to achieve tri- and tetracyclic triazoles [34]. Recently, Lautens et al. [41] described a one-pot synthesis of fused triazoles through CuAAC reaction

• According to the report of Kolarovič et al., the decarboxylative CuAAC reaction occurs efficiently with a CuSO4/NaAsc/DMSO catalytic system [6]. The palladium-catalyzed oxidative dehydrogenative coupling reaction may be effected by various oxidants [42][43] such as Ag2O, AgOAc, Ag2CO3, Na2S2O8, Cu(OPiv)2

Exploration of C–H and N–H-bond functionalization towards 1-(1,2-diarylindol-3-yl)tetrahydroisoquinolines

• Michael Ghobrial,
• Marko D. Mihovilovic and
• Michael Schnürch

Beilstein J. Org. Chem. 2014, 10, 2186–2199, doi:10.3762/bjoc.10.226

• salt [11]. This synthesis has been streamlined by cross dehydrogenative coupling (CDC) – a powerful method for C–C-bond formation via the C–H bonds of a pro-nucleophile and a pro-electrophile [12][13][14]. A landmark contribution published by Li and co-workers reported the successful introduction of

• wanted to use direct functionalization either via C–H activation or cross dehydrogenative coupling for C–C-bond-forming reactions avoiding the use of two prefunctionalized building blocks. Naturally, C–N-bond formation should proceed via Buchwald–Hartwig coupling. The target molecules can be considered

Iron-catalyzed decarboxylative alkenylation of cycloalkanes with arylvinyl carboxylic acids via a radical process

• Jincan Zhao,
• Hong Fang,
• Jianlin Han and
• Yi Pan

Beilstein J. Org. Chem. 2013, 9, 1718–1723, doi:10.3762/bjoc.9.197

• reactions. Additionally, metal-free methodologies, which use TBHP, PhI(OAc)2, TBAI, I2 or Lewis/Brønsted acids, have also been employed for cross-dehydrogenative coupling reactions [48][49][50][51][52][53][54][55][56][57]. Owing to the general low reactivity of cycloalkane C(sp3)–H bonds, the direct

A³-Coupling catalyzed by robust Au nanoparticles covalently bonded to HS-functionalized cellulose nanocrystalline films

• Jian-Lin Huang,
• Derek G. Gray and
• Chao-Jun Li

Beilstein J. Org. Chem. 2013, 9, 1388–1396, doi:10.3762/bjoc.9.155

• environmental pollution [1][2]. In the past few decades, aqueous-phase organic reactions have achieved great success [3][4][5]. The classic examples include the Grignard-type reactions [6][7], transition-metal catalyzed C–C bond formations [8][9] and cross-dehydrogenative coupling (CDC) reactions [10][11][12

Ru-catalyzed dehydrogenative coupling of carboxylic acids and silanes - a new method for the preparation of silyl ester

• Guo-Bin Liu and
• Hong-Yun Zhao

Beilstein J. Org. Chem. 2008, 4, No. 27, doi:10.3762/bjoc.4.27

• the transition metal-catalyzed cross-coupling of an active hydrogen-moiety containing substances such as water and alcohols with silanes [27]. There are still few examples of dehydrogenative coupling reaction of carboxylic acids with silanes. Silylating agents such as allyltrimethylsilane

• finding that a catalytic system of dodecacarbonyltriruthenium and ethyl iodide [Ru3(CO)12/EtI] effectively promotes the dehydrogenative coupling of carboxylic acids with silanes, yielding the corresponding silyl esters selectively. The results are summarized in Scheme 1 and Table 1–Table 4

• . Dehydrogenative coupling reactions were carried out by heating a mixture of carboxylic acid, silane and a catalytic amount of Ru3(CO)12/EtI in solvents under a nitrogen atmosphere for several hours (Scheme 1, Table 1–Table 4, dehydrocoupling reaction was monitored by GC). The transformation of propionic acid with

Conformational rigidity of silicon- stereogenic silanes in asymmetric catalysis: A comparative study

• Sebastian Rendler and
• Martin Oestreich

Beilstein J. Org. Chem. 2007, 3, No. 9, doi:10.1186/1860-5397-3-9

• reagents for the silicon-to-carbon chirality transfer. Kinetic resolution of secondary alcohols using a dehydrogenative coupling reaction. Catalytic cycle for hydrosilylation. Postulated catalytic cycle for dehydrogenative coupling. Supporting Information Supporting Information File 88: Supporting