A concise and efficient synthesis of benzimidazo[1,2-c]quinazolines through CuI-catalyzed intramolecular N-arylations

• Xinlong Pang,
• Chao Chen,
• Ming Li and
• Chanjuan Xi

Beilstein J. Org. Chem. 2015, 11, 2365–2369, doi:10.3762/bjoc.11.258

• -cyanoaniline (1) and diaryliodonium salts 2 based on our previously published method [13][14] (Scheme 1). Results and Discussion During the study of the synthesis of various carbocycles or heterocycles with copper catalysts [13][14][15][16][17], we found an interesting tandem reaction of o-cyanoanilines 1 and

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

• carbocycles by employing the RRM protocol starting with appropriate norbornene derivatives [43]. Recently, Kotha and Ravikumar [44] have found a new route to various polycyclic compounds by employing the DA reaction and the RRM protocol as key steps. To this end, the key building block 202 has been prepared

• approach toward C3-symmetric chiral trimethylsumanene 209. Triquinane synthesis via IMDA reaction and RRM protocol. RRM approach to polycyclic compounds. RRM strategy toward cis-fused bicyclo[3.3.0]carbocycles. RRM protocol towards the synthesis of bicyclic lactone 230. RRM approach to spiro heterocyclic

Synthesis and structures of ruthenium–NHC complexes and their catalysis in hydrogen transfer reaction

• Chao Chen,
• Chunxin Lu,
• Qing Zheng,
• Shengliang Ni,
• Min Zhang and
• Wanzhi Chen

Beilstein J. Org. Chem. 2015, 11, 1786–1795, doi:10.3762/bjoc.11.194

• such ruthenium complexes often contain coordinated aromatic carbocycles [27][28][29]. In contrast, only a few examples Ru(II) complexes of functionalized NHCs containing easily dissociating acetonitrile ligands have been studied [30][31][32]. We have reported the synthesis of some pyridine- and

Tandem cross enyne metathesis (CEYM)–intramolecular Diels–Alder reaction (IMDAR). An easy entry to linear bicyclic scaffolds

• Javier Miró,
• María Sánchez-Roselló,
• Álvaro Sanz,
• Fernando Rabasa,
• Carlos del Pozo and
• Santos Fustero

Beilstein J. Org. Chem. 2015, 11, 1486–1493, doi:10.3762/bjoc.11.161

• Ru-II catalyst) were applied to other aromatic alkynes 1 and dienes 2, affording a new family of linear carbocycles and heterocycles 3 in moderate yields (Table 2). Bicyclic lactone 3a, ketone 3b and lactam 3c were obtained in moderate yields following the tandem CEYM-IMDAR protocol (Table 2, entries

Scalable synthesis of 5,11-diethynylated indeno[1,2-b]fluorene-6,12-diones and exploration of their solid state packing

• Bradley D. Rose,
• Peter J. Santa Maria,
• Aaron G. Fix,
• Chris L. Vonnegut,
• Lev N. Zakharov,
• Sean R. Parkin and
• Michael M. Haley

Beilstein J. Org. Chem. 2014, 10, 2122–2130, doi:10.3762/bjoc.10.219

• . Our laboratory has been exploring a new class of PCHs based on the five structural isomers of indenofluorene [9]. In particular, the indeno[1,2-b]fluorene (IF, 1, Figure 1) skeleton is similar to linear oligoacenes, with the notable exception that the molecule contains two five-membered carbocycles

Chiral phosphines in nucleophilic organocatalysis

• Yumei Xiao,
• Zhanhu Sun,
• Hongchao Guo and
• Ohyun Kwon

Beilstein J. Org. Chem. 2014, 10, 2089–2121, doi:10.3762/bjoc.10.218

• result, phosphine-catalyzed asymmetric reactions are now powerful and versatile tools for the construction of C–C, C–N, C–O, and C–S bonds and for the syntheses of functionalized carbocycles and heterocycles [11][13][14]. In offering a general account of this field, herein we summarize the major

Allenylphosphine oxides as simple scaffolds for phosphinoylindoles and phosphinoylisocoumarins

• G. Gangadhararao,
• Ramesh Kotikalapudi,
• M. Nagarjuna Reddy and
• K. C. Kumara Swamy

Beilstein J. Org. Chem. 2014, 10, 996–1005, doi:10.3762/bjoc.10.99

• ][18][19] and as reagents in organic synthesis [20]. In our previous reports, we described the utility of phosphorus-based allenes in various cyclization reactions involving heteroatoms that could lead to phosphono/phosphinoyl hetero-/carbocycles [21][22][23][24][25][26][27][28][29][30]. The reported

Silver and gold-catalyzed multicomponent reactions

• Giorgio Abbiati and
• Elisabetta Rossi

Beilstein J. Org. Chem. 2014, 10, 481–513, doi:10.3762/bjoc.10.46

• between allenoate and phosphine. Thus, they believed that new cycloaddition reactions could be accessed if isocyanide was employed as a nucleophile instead of phosphine. The developed reaction allows the synthesis of five-membered carbocycles 86 by the silver hexafluoroantimonate-catalyzed three-component

A catalyst-free multicomponent domino sequence for the diastereoselective synthesis of (E)-3-[2-arylcarbonyl-3-(arylamino)allyl]chromen-4-ones

• Pitchaimani Prasanna,
• Pethaiah Gunasekaran,
• Subbu Perumal and
• J. Carlos Menéndez

Beilstein J. Org. Chem. 2014, 10, 459–465, doi:10.3762/bjoc.10.43

• to structurally diverse carbocycles and heterocycles, an area in which we have recently become interested [33][34][35][36][37][38][39][40][41][42]. Thus, the present study ia a continuation of our research program on the construction of novel heterocycles employing one-pot green domino-multicomponent

Recent applications of the divinylcyclopropane–cycloheptadiene rearrangement in organic synthesis

• Sebastian Krüger and
• Tanja Gaich

Beilstein J. Org. Chem. 2014, 10, 163–193, doi:10.3762/bjoc.10.14

• products; total synthesis; vinylcyclopropane–carbaldehyde rearrangement; Introduction The first documented divinylcyclopropane–cycloheptadiene rearrangement dates back to 1960 occuring during studies of Vogel and coworkers [1][2] on the thermal rearrangement of small carbocycles. Although the desired cis

Stereoselectively fluorinated N-heterocycles: a brief survey

• Xiang-Guo Hu and
• Luke Hunter

Beilstein J. Org. Chem. 2013, 9, 2696–2708, doi:10.3762/bjoc.9.306

• these types of approaches are examined in the following sections. 6.3 Diastereoselective fluorocyclisation The use of fluorocyclisation processes for the production of heterocycles and carbocycles has attracted considerable attention in recent years. Such processes have the advantage of forming multiple

New developments in gold-catalyzed manipulation of inactivated alkenes

• Michel Chiarucci and
• Marco Bandini

Beilstein J. Org. Chem. 2013, 9, 2586–2614, doi:10.3762/bjoc.9.294

• coworkers [60]. In particular, a range of densely functionalized heterobicyclic and carbocycles 90 were readily accessible in high yields and high stereoselectivity starting from properly functionalized sulfonium ylides 89 (Scheme 24). Computational and experimental investigations suggested the initial 20d

• aldehydes was performed under synergistic activation of the substrate by gold catalyst 20c and organocatalyst 116 (Scheme 30). The 5-membered hetero- and carbocycles 115 were obtained in moderate to good yield and interesting level of diastereo- and enantioselectivity, supporting the perfect compatibility

Gold(I)-catalyzed enantioselective cycloaddition reactions

• Fernando López and
• José L. Mascareñas

Beilstein J. Org. Chem. 2013, 9, 2250–2264, doi:10.3762/bjoc.9.264

• experimental data as well as theoretical calculations suggested that both cycloadducts, 14 and 15, arise from the same intermediate, the cycloheptanyl metal–carbene species VIII, which might evolve through a 1,2-hydrogen shift to give the seven-membered carbocycles 14 (Scheme 8, a), or by a ring-contraction

• /AgNTf2, or the phosphoramidite–gold complex (S,R,R)-Au16/AgNTf2, provides the corresponding cycloadducts 22 with good or high enantioselectivites (Scheme 14). The method constituted the first direct catalytic and enantioselective entry to oxygen-bridged eight-membered carbocycles and one of the few

Incorporation of perfluorohexyl-functionalised thiophenes into oligofluorene-truxenes: synthesis and physical properties

• Neil Thomson,
• Alexander L. Kanibolotsky,
• Joseph Cameron,
• Tell Tuttle,
• Neil J. Findlay and
• Peter J. Skabara

Beilstein J. Org. Chem. 2013, 9, 1243–1251, doi:10.3762/bjoc.9.141

• the p-orbital overlap, breaking the effective conjugation length [15]. This planarity can be perturbed by the steric effects of substituents attached to the hetero- or carbocycles in the conjugated backbone. In order to observe if the position of the perfluorohexyl chains would have an effect, two

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

• reactions. These reactions can be carried out either in an inter- or intramolecular fashion, though only a few examples have been described, due to the difficulty of enantiofacial differentiation for a nonactivated alkene. The intramolecular version has found application in the synthesis of both carbocycles

• transition state in which the lithium atom is coordinated to the remote π-bond [30][31][32]. This high stereocontrol has allowed the synthesis of enantiomerically pure carbocycles and heterocycles through diastereoselective cyclization of chiral nonracemic substrates [33][34][35][36][37][38]. Additionally

C–H Functionalization

• Huw M. L. Davies

Beilstein J. Org. Chem. 2012, 8, 1552–1553, doi:10.3762/bjoc.8.176

• , the field has experienced explosive growth and a large variety of new C–H functionalization methodologies have been developed. In particular, regioselective functionalization of sp2 C–H bonds has become a broadly flexible approach for the synthesis of complex aromatic carbocycles and heterocycles. In

Alkoxide-induced ring opening of bicyclic 2-vinylcyclobutanones: A convenient synthesis of 2-vinyl-substituted 3-cycloalkene-1-carboxylic acid esters

• Xiufang Ji,
• Zhiming Li,
• Quanrui Wang and
• Andreas Goeke

Beilstein J. Org. Chem. 2012, 8, 650–657, doi:10.3762/bjoc.8.72

• derivatives. Frequently employed ones include the thermal [2 + 2] cycloaddition of ketenes to alkenes and the polar addition of cyclopropyl ylides to carbonyls [1][2]. These methods generally allow regioselective as well as stereoselective syntheses of extensively substituted four-membered ring carbocycles

Recent developments in gold-catalyzed cycloaddition reactions

• Fernando López and
• José L. Mascareñas

Beilstein J. Org. Chem. 2011, 7, 1075–1094, doi:10.3762/bjoc.7.124

• (VIII) that participate in (4 + 2) annulations with polarized alkenes such as indoles, carbonyls, imines or silyl enol ethers [45]. Thus, different types of 6-membered carbocycles and heterocycles were prepared in good yields and notable regioselectivities. An example of these annulations, using indoles

• of the allene to afford a metal–allyl cation intermediate of type XXIX, which subsequently undergoes a concerted (4 + 3) cycloaddition reaction with the diene. The resulting metal carbene species (XXX) eventually evolves through a 1,2-hydrogen shift, leading to seven-membered carbocycles 50 and

Recent advances in the gold-catalyzed additions to C–C multiple bonds

• He Huang,
• Yu Zhou and
• Hong Liu

Beilstein J. Org. Chem. 2011, 7, 897–936, doi:10.3762/bjoc.7.103

• method to construct synthetically useful four-membered carbocycles. Ye et al. reported a new type of gold(I)-catalyzed ring expansion of an non-activated alkynylcyclopropane/sulfonamide to obtain (E)-2-alkylidenecyclobutanamines [73]. For example, treatment of alkynylcyclopropane 159 with TsNH2 and 5 mol

• high yields under optimal conditions. Zou et al. has developed a versatile approach to 5-, 6-, and 7-membered carbocycles via the gold-catalyzed cycloisomerization of cyclopropyl alkynyl acetates [96]. The homo-Rautenstrauch rearrangement of 1-cyclopropylpropargylic esters 216 gave cyclohexenones 217

Highly substituted benzannulated cyclooctanol derivatives by samarium diiodide-induced cyclizations

• Jakub Saadi,
• Irene Brüdgam and
• Hans-Ulrich Reissig

Beilstein J. Org. Chem. 2010, 6, 1229–1245, doi:10.3762/bjoc.6.141

• than those of the analogous eight-membered carbocycles. The configuration of 39 was assigned by using the following arguments: the relative configuration of the unlike-configured precursor should be transferred to the product and the bridgehead hydroxyl group should be in trans-relationship to the

Ring-alkyl connecting group effect on mesogenic properties of p-carborane derivatives and their hydrocarbon analogues

• Aleksandra Jankowiak,
• Piotr Kaszynski,
• William R. Tilford,
• Kiminori Ohta,
• Adam Januszko,
• Takashi Nagamine and
• Yasuyuki Endo

Beilstein J. Org. Chem. 2009, 5, No. 83, doi:10.3762/bjoc.5.83

• of structurally related series of mesogens containing rings A–D (Figure 2), it became apparent that the benzene ring–alkyl chain connection has a distinctly different impact on phase stability in derivatives of p-carborane (A) than in their isostructural carbocycles. For instance, a larger

• to analyze the effect of the replacement of an alkoxy in 14[6] with an ester group in 15[6]. The CH2O→OOC exchange dramatically destabilized the nematic phase for the 10- and 12-vertex p-carborane derivatives, while a much smaller effect was observed for the carbocycles [25]. Series 14 and 15 [25

• exclusively the nematic phase. Similar nematic behavior is observed for carbocycles in series 17–20 with the exception of 19D, which exhibits a SmA phase in addition to a N phase. In contrast, most carbocyclic derivatives in series 14[6]–16[6] display only smectic and soft crystalline polymorphs. The bicyclo

Allylsilanes in the synthesis of three to seven membered rings: the silylcuprate strategy

• Asunción Barbero,
• Francisco J. Pulido and
• M. Carmen Sañudo

Beilstein J. Org. Chem. 2007, 3, No. 16, doi:10.1186/1860-5397-3-16

• . Five and Six Membered Carbocycles Phenyldimethylsilylcyanocuprate 1, prepared by mixing one equivalent of phenyldimethylsilyllithium and one equivalent of copper(I) cyanide, reacts with 1,2-propadiene (bubbled from lecture bottles) at -40°C leading to the intermediate copper species 2, which on

• different from that observed for phenyldimethylsilylepoxyallylsilanes of type 23, giving nucleophilic substitution at the most substituted carbon of the epoxide (Scheme 6). [18][19] Three and Four Membered Carbocycles Oxoallylsilanes 4–7, 33 and 34, readily available via silylcuprate addition of 2 to enones

• key step is the syn addition of the tin cuprate to the acetylene, which controls the cis stereochemistry required for cyclization. [23] Seven Membered Carbocycles The use of nitriles and imines as electrophiles in the silylcupration of allene provides new alternatives for carbocyclization. Recently