Substituent effects on the regiochemistry of enone-alkene 2+2-photocycloadditions. Experimental results and FMO analysis

Suishu, Takaaki; Shimo, Tetsuro; Somekawa, Kenichi

doi:10.1016/s0040-4020(97)00105-1

Cited by 29 publications

(15 citation statements)

References 22 publications

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“… 42 − 44 Although somewhat simplistic, the chemistry of the triplet state is determined by the fact that the π* orbital is occupied by an electron, rendering the β-position nucleophilic and the α-position electrophilic. 273 , 274 Excitation thus induces a polarity reversal ( Umpolung ) relative to the ground state. As a result, intermolecular [2 + 2] photocycloaddition reactions with donor-substituted olefins (D = donor) occur to the HT product XII , with acceptor-substituted olefins (A = acceptor) to the HH product XIV .…”

Section: Direct Excitation and Sensitizationmentioning

confidence: 99%

Recent Advances in the Synthesis of Cyclobutanes by Olefin [2 + 2] Photocycloaddition Reactions

et al. 2016

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The [2 + 2] photocycloaddition is undisputedly the most important and most frequently used photochemical reaction. In this review, it is attempted to cover all recent aspects of [2 + 2] photocycloaddition chemistry with an emphasis on synthetically relevant, regio-, and stereoselective reactions. The review aims to comprehensively discuss relevant work, which was done in the field in the last 20 years (i.e., from 1995 to 2015). Organization of the data follows a subdivision according to mechanism and substrate classes. Cu(I) and PET (photoinduced electron transfer) catalysis are treated separately in sections 2 and 4, whereas the vast majority of photocycloaddition reactions which occur by direct excitation or sensitization are divided within section 3 into individual subsections according to the photochemically excited olefin.

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Section: Direct Excitation and Sensitizationmentioning

confidence: 99%

Recent Advances in the Synthesis of Cyclobutanes by Olefin [2 + 2] Photocycloaddition Reactions

et al. 2016

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“…In general, head-to-tail products are formed when the R group is electron-donating, while head-to-head products are produced when the R group is electron-withdrawing ( Scheme 3 , bottom). 47 − 50 …”

Section: [2 + 2] Photocycloadditionsmentioning

confidence: 99%

Photochemical Approaches to Complex Chemotypes: Applications in Natural Product Synthesis

2016

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The use of photochemical transformations is a powerful strategy that allows for the formation of a high degree of molecular complexity from relatively simple building blocks in a single step. A central feature of all light-promoted transformations is the involvement of electronically excited states, generated upon absorption of photons. This produces transient reactive intermediates and significantly alters the reactivity of a chemical compound. The input of energy provided by light thus offers a means to produce strained and unique target compounds that cannot be assembled using thermal protocols. This review aims at highlighting photochemical transformations as a tool for rapidly accessing structurally and stereochemically diverse scaffolds. Synthetic designs based on photochemical transformations have the potential to afford complex polycyclic carbon skeletons with impressive efficiency, which are of high value in total synthesis.

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“…Out of a multitude of more recent examples 15 one which illustrates the point is depicted below (Scheme 3). 19 The lactam 1 is attacked by the acceptor-substituted alkene acrylonitrile (2) to form predominantly the HH isomer of compound 4 whereas the reaction with ethyl vinyl ether (3) as a donor substituted alkene yields the HT isomer of adduct 5.…”

Section: Biographical Sketchmentioning

confidence: 99%

Stereoselective Intermolecular [2 + 2]-Photocycloaddition Reactions and Their Application in Synthesis

Bach

1998

Synthesis

300

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Stereoselective intermolecular [2+2]-photocycloaddition reactions of alkenes and Paternò-Büchi reactions are reviewed. For both reactions the regioselectivity and the simple diastereoselectivity which are relevant to the formation of a single product isomer are explained based on representative examples. In the subsequent sections the facial diastereoselectivity induced by the respective reaction partner is treated. Particular emphasis is given on synthetic applications of the cyclobutanes and oxetanes obtained by the photochemical key step. Consecutive reactions are discussed and the potential use of the four-membered ring intermediates is highlighted.

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Substituent effects on the regiochemistry of enone-alkene 2+2-photocycloadditions. Experimental results and FMO analysis

Cited by 29 publications

References 22 publications

Recent Advances in the Synthesis of Cyclobutanes by Olefin [2 + 2] Photocycloaddition Reactions

Recent Advances in the Synthesis of Cyclobutanes by Olefin [2 + 2] Photocycloaddition Reactions

Photochemical Approaches to Complex Chemotypes: Applications in Natural Product Synthesis

Stereoselective Intermolecular [2 + 2]-Photocycloaddition Reactions and Their Application in Synthesis

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Substituent effects on the regiochemistry of enone-alkene 2+2-photocycloadditions. Experimental results and FMO analysis

Cited by 29 publications

References 22 publications

Recent Advances in the Synthesis of Cyclobutanes by Olefin [2 + 2] Photocycloaddition Reactions

Recent Advances in the Synthesis of Cyclobutanes by Olefin [2 + 2] Photocycloaddition Reactions

Photochemical Approaches to Complex Chemotypes: Applications in Natural Product Synthesis

Stereoselective Intermolecular [2 + 2]-Photocycloaddition Reactions and Their Application in Synthesis

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Product

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Recent Advances in the Synthesis of Cyclobutanes by Olefin [2 + 2] Photocycloaddition Reactions

Recent Advances in the Synthesis of Cyclobutanes by Olefin [2 + 2] Photocycloaddition Reactions