Pentavalent organobismuth reagents. Part vi. Comparative migratory aptitudes of aryl groups in the arylation of phenols and enols by pentavalent bismuth reagents

Tris(polymethoxyphenyl)bismuth derivatives: Synthesis and reactivity

“…Thus, organobismuth reagents containing electron-rich aromatic fragments present a general pattern of reactivity similar to those of the analogs bearing electron-neutral substituents (for example, triphenylbismuth diacetate [21] or other pentavalent bismuth derivatives containing dimethyl-substituted phenyl groups [20]). It is worth noting that these facts do not fully correlate with the relative migratory aptitudes of the aryl groups (p-NO 2 C 6 H 4 ) C 6 H 5 > p-MeC 6 H 4 > p-MeOC 6 H 4 ), previously reported for the C-arylation reactions with non-symmetrical triarylbismuth carbonates [10], Ph n Ar 3Àn BiCO 3 (n = 1,2; Ar = p-NO 2 C 6 H 4 , p-MeC 6 H 4 and p-MeO C 6 H 4 ), or with unsymmetrical tetraarylbismuthonium salts [22], Ph 3 ArBiX (Ar = p-MeC 6 H 4 and p-MeOC 6 H 4 ). Thus, our observations show that organobismuth derivatives can be used in arylation reactions as a useful source of electronrich aryl groups as well as of electron-neutral and electronacceptor aryl fragments.…”

“…However, in the case of methoxy-substituted aryl groups, relatively few examples of arylation reactions were reported. Barton et al observed a lower reactivity for tri(p-methoxyphenyl)bismuth carbonate toward C-arylation of enolic and phenolic substrates [10]. On the other hand, Suzuki et al reported the strong influence of an ortho-methoxy group on the basicity and reactivity of triarylbismuth derivatives [11].…”

A Highly Enantioselective and Catalytic Aryl Transfer Reaction Using Mixed Triarylbismuthane and Dialkylzinc Reagents

“…Next, the aryl transfer reaction to aldehydes by using mixed triarylbismuthane and Me 2 Zn reagents was examined ( Table 2). The addition of the p-tolyl group to the aldehydes was achieved with the use of a mixed tris(4-methylphenyl)bismuthane [12] /Me 2 Zn reagent. When the addition to benzaldehyde (1g) was examined, diarylmethanol 2a was obtained in 89 % yield and 97 % ee (Table 2, Entry 1).…”

Photoinduced synthesis of unsymmetrical diaryl selenides from triarylbismuthines and diaryl diselenides

“…Diaryl diselenides 1b – e [67] and triarylbismuthines 2b – d [68] were synthesized according to the literature procedures.…”