Radical ligand transfer: a general strategy for radical functionalization

• David T. Nemoto Jr,
• Kang-Jie Bian,
• Shih-Chieh Kao and
• Julian G. West

Beilstein J. Org. Chem. 2023, 19, 1225–1233, doi:10.3762/bjoc.19.90

• beautiful decarboxylative azidation examples, combining iron-mediated photodecarboxylation via LMCT and azide RLT (Scheme 5) [11]. Irradiating a substoichiometric amount of iron(III) nitrate hydrate III in the presence of carboxylic acid, TMS azide, and sodium carbonate allows for direct synthesis of alkyl

When metal-catalyzed C–H functionalization meets visible-light photocatalysis

• Lucas Guillemard and
• Joanna Wencel-Delord

Beilstein J. Org. Chem. 2020, 16, 1754–1804, doi:10.3762/bjoc.16.147

• , liberating the expected product (Figure 28). In 2016, Wang et al. further demonstrated the possibility of extending this approach to the C(sp2)–H acylation of azo- and azoxybenzene derivatives (Figure 29) [90]. Similarly, acyl radicals generated by photodecarboxylation of α-ketoacids were engaged in a dual

[3 + 2] Cycloaddition with photogenerated azomethine ylides in β-cyclodextrin

• Margareta Sohora,
• Leo Mandić and
• Nikola Basarić

Beilstein J. Org. Chem. 2020, 16, 1296–1304, doi:10.3762/bjoc.16.110

• reactions [8]. Azomethine ylides can be formed by several photochemical or thermal catalytic methods [5][6][7], including photodecarboxylation of phthalimide derivatives of α-amino acids such as N-phthaloylglycine (1) [9][10]. Phthalimide is a versatile chromophore that has been used in the synthesis of

• the macrocyclic host affected the stereochemistry of the reaction. Moreover, we studied photodecarboxylation reactions initiated by the phthalimide chromophore [17][18][19] and applied them in cyclizations with memory of chirality [20] and diastereoselective peptide cyclizations [21

• ]. Photodecarboxylations were also intensively investigated in a series of nonsteroidal anti-inflammatory drugs [22][23][24] such as ketoprofen [25][26][27][28][29][30][31][32][33][34], due to photoallergic responses initiated by photodecarboxylation of these drugs [35]. Stereoselectivity in photochemical reactions can be

The photodecarboxylative addition of carboxylates to phthalimides as a key-step in the synthesis of biologically active 3-arylmethylene-2,3-dihydro-1H-isoindolin-1-ones

• Ommid Anamimoghadam,
• Saira Mumtaz,
• Anke Nietsch,
• Gaetano Saya,
• Cherie A. Motti,
• Jun Wang,
• Peter C. Junk,
• Ashfaq Mahmood Qureshi and
• Michael Oelgemöller

Beilstein J. Org. Chem. 2017, 13, 2833–2841, doi:10.3762/bjoc.13.275

• ; arylmethylenedihydroisoindolinones; photochemistry; photodecarboxylation; phthalimide; Introduction Phthalimides and their related 3-alkyl- and 3-arylmethylene-2,3-dihydro-1H-isoindolin-1-ones play an important role in medicinal chemistry due to their biological activities for a wide range of therapeutic applications [1][2][3][4

• ]. Selected transformations have been furthermore realized on large multigram scales [25][34][35] and in continuous-flow mode [36][37][38][39][40]. The photodecarboxylation procedure was subsequently applied to the synthesis of 2-dialkylaminoalkyl-3-arylmethylene-2,3-dihydro-1H-isoindolin-1-ones. The

• one of the N-ethyl groups of the side chain. The mechanism of the photodecarboxylation is well established (Scheme 7) and involves triplet sensitization by acetone and electron transfer between the phenylacetate and the excited phthalimide [55][56][57]. Subsequent decarboxylation, radical combination

Flow photochemistry: Old light through new windows

• Jonathan P. Knowles,
• Luke D. Elliott and
• Kevin I. Booker-Milburn

Beilstein J. Org. Chem. 2012, 8, 2025–2052, doi:10.3762/bjoc.8.229

• performed. Although the results demonstrated the quantum yield for the gas-phase reaction in simulated solar light to be substantially lower than that of the solution-state reaction (0.16% versus 5.5%), it was shown that conversions of up to 43% could be achieved [57]. Photodecarboxylation reactions The

• acetone-sensitised photodecarboxylation chemistry initially developed by Griesbeck [58] under batch conditions was suggested as being ideally suited to microflow conditions [59][60]. The chemistry involves the decarboxylative addition of potassium carboxylates to phthalimides, thus offering an alternative

• to Grignard reagents that can be employed under aqueous conditions [58]. Initially, the α-photodecarboxylation of phthaloyl glycine 44 (Scheme 16) was investigated in a microflow Dwell device and compared with the reaction under batch conditions. The microflow reactor required a shorter residence

Photoreactions of cyclic sulfite esters: Evidence for diradical intermediates

• Rick C. White,
• Benny E. Arney Jr. and
• Heiko Ihmels

Beilstein J. Org. Chem. 2012, 8, 1208–1212, doi:10.3762/bjoc.8.134

• in the photochemistry of vicinal diaryloxiranes based on the photochemical formation of methyl ethers in methanol solution [8]. Mechanistically, stereoselective oxygen scrambling was found in the photoextrusion of carbon dioxide from benzyl benzoate esters [9]. Furthermore, photodecarboxylation

Microphotochemistry: 4,4'-Dimethoxybenzophenone mediated photodecarboxylation reactions involving phthalimides

• Oksana Shvydkiv,
• Kieran Nolan and
• Michael Oelgemöller

Beilstein J. Org. Chem. 2011, 7, 1055–1063, doi:10.3762/bjoc.7.121

• intra- and intermolecular photodecarboxylation reactions involving phthalimides have been examined under microflow conditions. Conversion rates, isolated yields and chemoselectivities were compared to analogous reactions in a batch photoreactor. In all cases investigated, the microreactions gave

• superior results thus proving the superiority of microphotochemistry over conventional technologies. Keywords: microflow; microreactor; photochemistry; photodecarboxylation; phthalimide; Introduction Organic photochemistry is a highly successful synthesis method that allows the construction of complex

• [20][21][22][23] and specialized micro-photoreactors for laboratory- to technical-scale synthesis have been developed [24][25][26]. We have recently reported on acetone-sensitized photodecarboxylation (PDC) reactions of phthalimides in a commercially available microreactor [27]. The photochemistry of

Photoinduced electron-transfer chemistry of the bielectrophoric N-phthaloyl derivatives of the amino acids tyrosine, histidine and tryptophan

• Axel G. Griesbeck,
• Jörg Neudörfl and
• Alan de Kiff

Beilstein J. Org. Chem. 2011, 7, 518–524, doi:10.3762/bjoc.7.60

• and tryptophan 8–10 was studied with respect to photoinduced electron-transfer (PET) induced decarboxylation and Norrish II bond cleavage. Whereas exclusive photodecarboxylation of the tyrosine substrate 8 was observed, the histidine compound 9 resulted in a mixture of histamine and preferential

• transfer product 2. On the other hand, phthaloyl derivatives of C-unprotected α-amino acids (e.g., derivatives of Gly, Ala, Val, Ile, Phe) undergo efficient photodecarboxylation to yield the corresponding amines, β-amino acids are converted to benzazepines, and γ-amino acids to benzopyrrolizidines (Scheme

• efficiently with decarboxylation when the reaction is triplet-sensitized [7]. Photodecarboxylation is followed by PET cyclization to give 6, whereas the lactone 7 originates from PET-induced sulfur oxidation and radical ion trapping without subsequent decarboxylation. Similar effects were observed for the