Diels–Alder reactions of myrcene using intensified continuous-flow reactors

• Christian H. Hornung,
• Miguel Á. Álvarez-Diéguez,
• Thomas M. Kohl and
• John Tsanaktsidis

Beilstein J. Org. Chem. 2017, 13, 120–126, doi:10.3762/bjoc.13.15

• thermal isomerization at temperatures between 400 and 600 °C. This was first described by Goldblatt and Palkin in 1947 [11]. Myrcene is a very versatile molecule that can act as the starting material for several valuable compounds. The industrial production of a series of top-selling flavors and

Selected synthetic strategies to cyclophanes

• Sambasivarao Kotha,
• Mukesh E. Shirbhate and
• Gopalkrushna T. Waghule

Beilstein J. Org. Chem. 2015, 11, 1274–1331, doi:10.3762/bjoc.11.142

Thermodynamically stable [4 + 2] cycloadducts of lanthanum-encapsulated endohedral metallofullerenes

• Yuta Takano,
• Yuki Nagashima,
• M. Ángeles Herranz,
• Nazario Martín and
• Takeshi Akasaka

Beilstein J. Org. Chem. 2014, 10, 714–721, doi:10.3762/bjoc.10.65

• 4a was heated to a temperature of 250 °C, selective decomposition of 3a was observed (Figure 6). Since the peak of pristine La@C82 at ca. 30 min is observed after heating (see Figure 6b), most probably the detachment of the addend is taking place and a thermal isomerization thereafter. After HPLC

Cyclization of substitued 2-(2-fluorophenylazo)azines to azino[1,2-c]benzo[d][1,2,4]triazinium derivatives

• Aleksandra Jankowiak,
• Emilia Obijalska and
• Piotr Kaszynski

Beilstein J. Org. Chem. 2013, 9, 1873–1880, doi:10.3762/bjoc.9.219

• -isomers cannot be populated thermally due to the high E → Z thermal isomerization barrier (ΔG‡298 > 35 kcal/mol) [7]. The Z-forms however, thermally and also photochemically isomerize back to the more stable E-isomers, and the rates are substituent depended [12]. Thus, with the broadband irradiation a

The chemistry of bisallenes

• Henning Hopf and
• Georgios Markopoulos

Beilstein J. Org. Chem. 2012, 8, 1936–1998, doi:10.3762/bjoc.8.225

• superior route to 88 consists of the thermal isomerization of hexakis(trimethylsilyl)benzene (89) [71][72]. Under flash vacuum pyrolysis conditions (400 °C, <0.01 Tor) 88 is produced from 89 as a mixture with several of its isomers (see below), but heating of the aromatic substrate at 200 °C for 10 h

• [87], go back to the 1930s (Scheme 31). Again, a thermal isomerization of a 1,5-hexadiyne derivative to a conjugated bisallene was employed, a process that will be discussed in detail in Section 1.4.1. Hexakis(tert-butylethynyl)ethane (117), when heated in alcoholic solution, isomerizes to the

Control over molecular motion using the cis–trans photoisomerization of the azo group

• Estíbaliz Merino and
• María Ribagorda

Beilstein J. Org. Chem. 2012, 8, 1071–1090, doi:10.3762/bjoc.8.119

• . The isomers (trans,trans) and (cis,cis) are 28 and 2.6 kcal∙mol−1 more stable than the intermediate isomer, respectively. The large energy difference between (trans,trans) and (trans,cis) isomers indicates the ring strain that exists in the (trans,cis) isomer, and the thermal isomerization from (cis

Molecular switches and cages

• Dirk Trauner

Beilstein J. Org. Chem. 2012, 8, 870–871, doi:10.3762/bjoc.8.97

• (Rück-Braun, Hoppmann). Two reviews discuss cis-azobenzenes with rapid thermal isomerization kinetics (Velasco), and highlight the azobenzene moiety as one of the smallest light-driven molecular motors conceivable (Merino). Issues of bistability are also addressed in an account on shape-persistent

Discovery of practical production processes for arylsulfur pentafluorides and their higher homologues, bis- and tris(sulfur pentafluorides): Beginning of a new era of “super-trifluoromethyl” arene chemistry and its industry

• Teruo Umemoto,
• Lloyd M. Garrick and
• Norimichi Saito

Beilstein J. Org. Chem. 2012, 8, 461–471, doi:10.3762/bjoc.8.53

• to be thermal isomerization of trans-2a to cis-2a with an acid catalyst, suggesting that the cis-isomer is more thermodynamically stable than the trans-isomer. With ZnF2/SbCl5 the cis-isomer was barely detected (run 11, Table 3). The ratio of trans-2a:cis-2a:PhSF5 was 385:0:100 after 10 min; 63:trace

An efficient and practical entry to 2-amido-dienes and 3-amido-trienes from allenamides through stereoselective 1,3-hydrogen shifts

• Ryuji Hayashi,
• John B. Feltenberger,
• Andrew G. Lohse,
• Mary C. Walton and
• Richard P. Hsung

Beilstein J. Org. Chem. 2011, 7, 410–420, doi:10.3762/bjoc.7.53

• thermal isomerization of exocyclic allenes to dienes via radical intermediates see [4][5][6][7][8][9][10][11][12]), whereby controlling E/Z ratios of the resulting diene remains a difficult problem. On the other hand, a stepwise isomerization of allenes via acid-, base-, or metal-mediated conditions seem

• argument could be used to rationalize the regioselective 1,3-hydrogen shift when acid was used. It is noteworthy that this charged transition state could also be adopted for the thermal isomerization. While still being a neutral transition state, the nitrogen atom could facilitate a polarized transition