Radical cross-coupling

Photoaddition of. V-melhylaniline to phenantherene ring via C—O cleavage also occurs to give N-, <>-, and p-(phenanthrylmethyl)-substituted /V-mcthylani-lines, as shown in Scheme 115 [390], It is explained in terms of one-electron transfer from iV-methylanilinc to the phenanthrene derivatives, followed by proton transfer and the radical cross-coupling. 

The introduction of a styryl group at the C-6 position of penams finds its application in the intrinsic /3-lactamase inhibition activity of 6-vinyl penicillins 26 (see Sections 2.03.5.9 and 2.03.12.4). Its incorporation can be performed via a cobaltoxime-mediated radical cross-coupling reaction between a 6-bromopenicillanate and styrene (Scheme 15) < 1996BML2289>. 

Scheme 15 Cobaltoxime-mediated radical cross-coupling reaction.

In contrast to the most synthetic strategies involving ionic elongation reactions at C-l of aldoses, a synthesis of KDO based on the photochemically induced radical cross-coupling of a-ethoxyacrylnitrile with an alkyl cobaltoxime derivative at C-6 of D-mannose has been reported by Branchaud et al. [106], Thus, treatment of 6-iodo-D-... 

The experiments were conducted directly in the cavity of the EPR spectrometer [94]. Other reactions of note summarized in Table I include the decarboxylation of carboxylic acids ( 90% selectivity) [75, 88] the dehydrogenation of organonitriles, equation (24) [88], and the radical cross coupling observed when solutions of alkanes and ethers are simultaneously irradiated in the presence of Q4W10O32, equation (25) [75,90]. In equation... 

In early 2015, Xiao and co-workers developed a redox-neutral radical-radical cross-coupling protocol, allowing for direct a-allylation of amines by dual visible light and palladium catalysis (Scheme 3.14) [60]. Both tertiary amines and secondary amines could undergo the aUylation reaction smoothly. It renders a rapid and elegant access to 8-oxoprotoberberine derivatives. To get mechanistic insights, EPR spin trapping experiment with DMPO was carried out and the proposed a-aminoalkyl radical was determined. 

When performing the Kumada-Corriu cross-couplings in the presence of an alkyl iodide such as /-PrI, a radical cross-coupling mechanism operates, allowing the performance of such cross-couplings at ambient temperature with less expensive aryl bromides (Scheme 2-8). The use of powerful Pd catalysts such as Pd(0)/5-Phos or PEPPSI is mandatory for achieving this radical-mediated cross-coupling. 

Due to the similarity of the intermediate polymer radicals, cross-coupling reactions should occur when reactions (1) and (4) are run simultaneously for example ... 

---