Regioselectivity of the S_EAr-based cyclizations and S_EAr-terminated annulations of 3,5-unsubstituted, 4-substituted indoles

• Jonali Das and
• Sajal Kumar Das

Beilstein J. Org. Chem. 2022, 18, 293–302, doi:10.3762/bjoc.18.33

• regioselectivity in favor of the 4,5-fused indole system. Based on their experimental and computational investigations, the researchers hypothesized that Thorpe–Ingold effect could induce dispersive interactions between the indole and styrene moieties, triggering the preferential formation of the 3,4-fused indoles

Methodologies for the synthesis of quaternary carbon centers via hydroalkylation of unactivated olefins: twenty years of advances

• Thiago S. Silva and
• Fernando Coelho

Beilstein J. Org. Chem. 2021, 17, 1565–1590, doi:10.3762/bjoc.17.112

• transferred preferentially to the terminal carbon of an electron-deficient olefin, yielding 41 in 72% yield after 4 days (Scheme 20). The byproducts of isomerization and reduction were also observed under these conditions, and the authors used the Thorpe–Ingold effect to favor the cyclization product by

Supramolecular polymers with reversed viscosity/temperature profile for application in motor oils

• Jan-Erik Ostwaldt,
• Christoph Hirschhäuser,
• Stefan K. Maier,
• Carsten Schmuck and
• Jochen Niemeyer

Beilstein J. Org. Chem. 2021, 17, 105–114, doi:10.3762/bjoc.17.11

• transformation at elevated temperatures, leading to the desired viscosity effect. The direct comparison of the linkers in A and B strongly suggests that the Thorpe–Ingold effect induced by the gem-dimethyl unit is crucial for the supramolecular polymerization, thus indicating that indeed a ring–chain

The synthesis of functionalized bridged polycycles via C–H bond insertion

• Jiun-Le Shih,
• Po-An Chen and
• Jeremy A. May

Beilstein J. Org. Chem. 2016, 12, 985–999, doi:10.3762/bjoc.12.97

• oxide oxidant. Notably, a hindered ligand was again necessary for bridged-bicycle formation – in this case the diadamantyl phosphine 106. The Thorpe–Ingold effect was also found to be highly beneficial for the reaction. An interesting mechanistic study using a less selective substrate showed that the

Recent advances in the electrochemical construction of heterocycles

• Robert Francke

Beilstein J. Org. Chem. 2014, 10, 2858–2873, doi:10.3762/bjoc.10.303

• case due to the Thorpe–Ingold effect [46]. Recently, Zeng, Little and co-workers reported a new electrochemical method for the preparation of 3,5-disubstituted isoxazoles from chalcone oximes 20 (Scheme 8) [47]. The electrolysis of 20 is carried out in an undivided cell under galvanostatic conditions

Cyclization–endoperoxidation cascade reactions of dienes mediated by a pyrylium photoredox catalyst

• Nathan J. Gesmundo and
• David A. Nicewicz

Beilstein J. Org. Chem. 2014, 10, 1272–1281, doi:10.3762/bjoc.10.128

• to the investigation of diene structures similar to successful endoperoxidation substrate 2a. Removal of the geminal dimethyl group (2f) resulted in significantly diminished yields of the endoperoxide adduct, likely due to the lack of a Thorpe–Ingold effect present in 2a. These experiments also

Phosphinate-containing heterocycles: A mini-review

• Olivier Berger and
• Jean-Luc Montchamp

Beilstein J. Org. Chem. 2014, 10, 732–740, doi:10.3762/bjoc.10.67

• synthesized in two steps at room temperature, first, by a nucleophilic attack of methyl hypophosphite on oxazolidine 60 followed by an intramolecular cyclization, this time without base catalyzed transesterification. The authors explained this difference of reactivity by the Thorpe–Ingold effect [38]. Indeed

Concise, stereodivergent and highly stereoselective synthesis of cis- and trans-2-substituted 3-hydroxypiperidines – development of a phosphite-driven cyclodehydration

• Peter H. Huy,
• Julia C. Westphal and
• Ari M. P. Koskinen

Beilstein J. Org. Chem. 2014, 10, 369–383, doi:10.3762/bjoc.10.35

• arrangement might be stabilized through a hydrogen bridge between the NH proton and the O atom of the secondary OH group and a (weak) Thorpe–Ingold effect by the substituent R. The much less nucleophilic Boc-carbamate 12c was not converted to the desired piperidine 13c (entry 4). Here only starting material

The difluoromethylene (CF₂) group in aliphatic chains: Synthesis and conformational preference of palmitic acids and nonadecane containing CF₂ groups

• Yi Wang,
• Ricardo Callejo,
• Alexandra M. Z. Slawin and
• David O’Hagan

Beilstein J. Org. Chem. 2014, 10, 18–25, doi:10.3762/bjoc.10.4

• that it can accommodate angle strain. For example CF2 compounds display an apparent Thorpe–Ingold effect relative to CH2 in ring closing metathesis reactions (RCM) to cycloheptene [8]. Comparison of the rates of reaction with different substituents at the C-5 position of the diene precursors 1a–d

An intramolecular inverse electron demand Diels–Alder approach to annulated α-carbolines

• Zhiyuan Ma,
• Feng Ni,
• Grace H. C. Woo,
• Sie-Mun Lo,
• Philip M. Roveto,
• Scott E. Schaus and
• John K. Snyder

Beilstein J. Org. Chem. 2012, 8, 829–840, doi:10.3762/bjoc.8.93

• , with the gem dimethyl substituted propargylic carbon, was run in diglyme at a higher temperature (160 °C, 30 min), the cycloaddition proceeded in good yield to give the desired product 14c (91%; Table 4, entry 3), presumably aided by the Thorpe–Ingold effect [88][89][90]. To confirm the importance of

Improved syntheses of high hole mobility phthalocyanines: A case of steric assistance in the cyclo-oligomerisation of phthalonitriles

• Daniel J. Tate,
• Rémi Anémian,
• Richard J. Bushby,
• Suwat Nanan,
• Stuart L. Warriner and
• and Benjamin J. Whitaker

Beilstein J. Org. Chem. 2012, 8, 120–128, doi:10.3762/bjoc.8.14

• yield. The phthalocyanine with eight α-isoheptyl substituents gives a high time-of-flight hole mobility of 0.14 cm2·V−1·s−1 within the temperature range of the columnar hexagonal phase, that is 169–189 °C. Keywords: high hole mobility; phthalocyanine; steric assistance; Thorpe–Ingold effect; time-of

• conformational space available to the intermediate, they would favour cyclisation. This phenomenon is clearly related to the effect of gem-dimethyl groups on the cyclisation of acyclic compounds (the Thorpe–Ingold effect) [37]. From the standpoint of making phthlocyanine-based liquid crystals, its importance is

Intramolecular hydroamination of alkynic sulfonamides catalyzed by a gold–triethynylphosphine complex: Construction of azepine frameworks by 7-exo-dig cyclization

• Hideto Ito,
• Tomoya Harada,
• Hirohisa Ohmiya and
• Masaya Sawamura

Beilstein J. Org. Chem. 2011, 7, 951–959, doi:10.3762/bjoc.7.106

• caused a drastic decrease in the ease of the cyclization, which necessitated much more harsh reaction conditions (5 mol % Au, 80 °C, 4–12 h, Table 3, entries 4–6) than those for the reaction of the parent substrate 4a (0.5 mol % Au, 25 °C, 18 h, Table 1, entry 1). This means that the Thorpe–Ingold effect

The use of silicon- based tethers for the Pauson- Khand reaction

• Adrian P. Dobbs,
• Ian J. Miller and
• Saša Martinović

Beilstein J. Org. Chem. 2007, 3, No. 21, doi:10.1186/1860-5397-3-21

• 180°. This large angle would mean that the 'arms' would never be close enough together to undergo cycloaddition. Therefore the angle must be decreased and this can be accomplished by increasing the size of the non-reactive substituents as stated by the Thorpe-Ingold effect. Denmark stated that the