Hydroarylation of Alkenes by Protonation/Friedel–Crafts Trapping: HFIP-Mediated Access to Per-aryl Quaternary Stereocenters

Nielsen, Christian D.-T.; White, Andrew J. P.; Sale, David; Burés, Jordi; Spivey, Alan C.

doi:10.1021/acs.joc.9b02393

Cited by 28 publications

(12 citation statements)

References 71 publications

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“…A combination of TsOH and HFIP was exploited for a Markovnikov-selective intermolecular type hydroarylation of various styrenyl alkenes such as indenes and 1,1-diarylsubstituted alkenes with electron-rich arenes (Scheme ). The reaction proceeds via protonation of the alkene to generate an HFIP-stabilized benzylic carbocation, which was trapped by an electron-rich arene nucleophile to deliver the desired hydroarylated product. The reaction did not proceed in i -PrOH.…”

Section: C–c Bond-forming Reactionsmentioning

confidence: 99%

HFIP in Organic Synthesis

et al. 2022

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1,1,1,3,3,3-Hexafluoroisopropanol (HFIP) is a polar, strongly hydrogen bond-donating solvent that has found numerous uses in organic synthesis due to its ability to stabilize ionic species, transfer protons, and engage in a range of other intermolecular interactions. The use of this solvent has exponentially increased in the past decade and has become a solvent of choice in some areas, such as C–H functionalization chemistry. In this review, following a brief history of HFIP in organic synthesis and an overview of its physical properties, literature examples of organic reactions using HFIP as a solvent or an additive are presented, emphasizing the effect of solvent of each reaction.

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Section: C–c Bond-forming Reactionsmentioning

confidence: 99%

HFIP in Organic Synthesis

et al. 2022

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“…AB-KP, AB-Me and KP-Me were prepared as previously described in the literature. 17,21,24 UV-Vis absorption. UV absorption spectra were registered on a Cary 50 spectrophotometer (Varian) using a quartz cuvette of 1 cm optical path and 3 mL capacity.…”

Section: Methodsmentioning

confidence: 99%

Triplet Stabilization for the Enhanced Drug Photorelease from Sunscreen-Based Photocages

Lineros‐Rosa¹,

Cuquerella²,

Francés‐Monerris³

et al. 2020

Preprint

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<p>Recently, sunscreen-based drug photocages have been introduced to provide UV protection to photoactive drugs, thus increasing their photosafety. Here, combined experimental and theoretical studies performed on a photocage based on the commercial UVA filter avobenzone (AB) and on the photosensitizing non-steroidal anti-inflammatory drug ketoprofen (KP) are presented unveiling the photophysical processes responsible for the light-triggered release. Particular attention is paid to solvent stabilization of the drug and UV filter excited states, respectively, which leads to a switching between the triplet excited state energies of the AB and KP units. Most notably, <a>we show that the stabilization of the AB triplet excited state in ethanol solution is the key requirement for an efficient photouncaging. By contrast, in apolar solvents, in particular hexane, KP has the lowest triplet excited state, hence acting as an energy acceptor quench</a>ing the AB triplet manifold, thus inhibiting the desired photoreaction.</p>

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“…1 The development of succinct and efficient approaches for the production of anisoles and their derivatives has therefore attracted significant interest in the past few decades. 2–5 In particular, the C–H alkylation of anisoles with alkenes represents one of the most atom-efficient and environmentally benign synthetic routes. 2–4 Although the well-known Friedel–Crafts type reactions of anisoles with alkenes via carbocation intermediates have been extensively investigated with Lewis and Brønsted acids as the catalysts, the control of regioselectivity has been problematic; a mixture of ortho - and para -regioisomers are always concomitantly generated in the reaction process (Scheme 1a).…”

Section: Introductionmentioning

confidence: 99%