Copper-catalyzed aerobic radical C–C bond cleavage of N–H ketimines

• Ya Lin Tnay,
• Gim Yean Ang and
• Shunsuke Chiba

Beilstein J. Org. Chem. 2015, 11, 1933–1943, doi:10.3762/bjoc.11.209

• cleavage of N–H ketimines. Treatment of N–H ketimines having an α-sp3 hybridized carbon under Cu-catalyzed aerobic reaction conditions resulted in a radical fragmentation with C–C bond cleavage to give the corresponding carbonitrile and carbon radical intermediate. This radical process has been applied for

• 1aa most likely via the corresponding iminyl radical, that undergoes radical fragmentation to afford the corresponding C-radical and carbonitrile 5a [55]. Thus, it is deduced that oxaspirocyclohexadienone 3a was formed through oxygenation of the putative C-radical. Moreover, in this transformation

Fates of imine intermediates in radical cyclizations of N-sulfonylindoles and ene-sulfonamides

• Hanmo Zhang,
• E. Ben Hay,
• Stephen J. Geib and
• Dennis P. Curran

Beilstein J. Org. Chem. 2015, 11, 1649–1655, doi:10.3762/bjoc.11.181

• ; radical cyclization; radical fragmentation; spiro-indoles; Introduction Radical additions and cyclizations of ene-sulfonamides are useful reactions in a number of settings. The primary products of these reactions, α-sulfonamidoyl radicals, are often thought to undergo elimination reactions of sulfonyl

Direct and indirect single electron transfer (SET)-photochemical approaches for the preparation of novel phthalimide and naphthalimide-based lariat-type crown ethers

• Dae Won Cho,
• Patrick S. Mariano and
• Ung Chan Yoon

Beilstein J. Org. Chem. 2014, 10, 514–527, doi:10.3762/bjoc.10.47

• chemical yields and regiochemical selectivities of these photochemical reactions are governed by several factors. In case where the rates of the intrasite-SET are low compared to those of cation radical fragmentation reactions (kE1 or kE2), photoproduct ratios are governed by the relative rates of (1) SET

Copper-catalyzed aerobic aliphatic C–H oxygenation with hydroperoxides

• Pei Chui Too,
• Ya Lin Tnay and
• Shunsuke Chiba

Beilstein J. Org. Chem. 2013, 9, 1217–1225, doi:10.3762/bjoc.9.138

• hydroperoxides 1 prior to the 1,5-H radical shift (Scheme 4). Presumably, radical fragmentation of O-radicals occurs to give the corresponding ketones 7, which are reduced by LiAlH4 in the next step to give alcohols 6 (Scheme 4). The reaction of a secondary hydroperoxide such as 1o, however, afforded C–H

Reduction of arenediazonium salts by tetrakis(dimethylamino)ethylene (TDAE): Efficient formation of products derived from aryl radicals

• Mohan Mahesh,
• John A. Murphy,
• Franck LeStrat and
• Hans Peter Wessel

Beilstein J. Org. Chem. 2009, 5, No. 1, doi:10.3762/bjoc.5.1

• translocation) by the aryl radical 67 from the carbon atom in the α-position to the nitrogen atom of the indoline nucleus within the same molecule. The indolinyl radical 71 might follow pathway A and undergo radical fragmentation to the intermediate 75 which would eventually tautomerise to indole (63). The

• precedent for this radical fragmentation of the sulfonyl group comes from the previous work of our group [71], where a similar indolinyl radical underwent a radical cleavage of N-S bond to eliminate the sulfonyl group. Indole sulfonamide 64 could be explained by deprotonation of radical 71 by TDAE to form

Do α-acyloxy and α-alkoxycarbonyloxy radicals fragment to form acyl and alkoxycarbonyl radicals?

• Dennis P. Curran and
• Tiffany R. Turner

Beilstein J. Org. Chem. 2006, 2, No. 10, doi:10.1186/1860-5397-2-10

• whether this product arises through a slow radical fragmentation process or an inefficient, chain-breaking oxidative process. Introduction Most organic radical reactions occur through a cascade of two or more individual steps [1][2]. Knowledge of the nature and rates of these steps – in other words, the

• give 15 and 16a,b is the competition step, and a standard plot of the ratio of products as a function of tin hydride concentration should provide a straight line passing through the origin if radical fragmentation competes with reduction. Alternatively, oxidation of 13a,b to cation 17a,b will