- TBuLi-Mediated One-Pot Direct Highly Selective Cross-Coupling of Two Distinct Aryl Bromides
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A Pd-catalyzed direct cross-coupling of two distinct aryl bromides mediated by tBuLi is described. The use of [Pd-PEPPSI-IPr] or [Pd-PEPPSI-IPent] as catalyst allows for the efficient one-pot synthesis of unsymmetrical biaryls at room temperature. The key for this selective cross-coupling is the use of an ortho-substituted bromide that undergoes lithium-halogen exchange preferentially. Bro to Bro: A palladium-catalyzed direct cross-coupling of two distinct aryl bromides mediated by tBuLi is described. The use of [Pd-PEPPSI-IPr] or [Pd-PEPPSI-IPent] as catalyst allows for the efficient one-pot synthesis of unsymmetrical biaryls at room temperature. The key for this selective cross-coupling is the use of an ortho-substituted bromide that undergoes lithium-halogen exchange preferentially.
- Vila, Carlos,Cembellín, Sara,Hornillos, Valentín,Giannerini, Massimo,Fa?anás-Mastral, Martín,Feringa, Ben L.
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supporting information
p. 15520 - 15524
(2015/11/03)
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- Rates of decarboxylation of acyloxy radicals formed in the photocleavage of substituted 1-naphthylmethyl alkanoates
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Rates of decarboxylation (kCO2R) have been estimated for the acyloxy racicals 7a-f formed in the photolysis of substituted 1-naphthylmethyl 6a-f. These rates are on a mechanism involving initial carbon-oxygen homolytic bond cleavage from the excited singlet state. The products are formed by two competing pathways: electron transfer in the radical pair to give an ion pair and decarboxylation. Measured product yields along with an of the electron-transfer rate (kET) allow calculation of kCO2R as a function of R. The values obtained are the following (R, k (109 s-1)): CH3, 3CH2, 2.0; (CH3)2CH, 6.5; (CH3)3C, 11; PhCH2, 5.0; PhCH2CH2, 2.3.
- Hilborn, James W.,Pincock, James A.
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p. 2683 - 2686
(2007/10/02)
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