Remarkable Substituent Effects on the Oxidizing Ability of Triarylbismuth Dichlorides in Alcohol Oxidation

Abstract

Substituent effects on the oxidizing ability of triarylbismuth dichlorides were examined by intermolecular and intramolecular competition experiments on geraniol oxidation in the presence of DBU. It was found that the oxidizing ability of the dichlorides increases with increasing electron-withdrawing ability of the para substituents, and by introduction of a methyl group at the ortho position of the aryl ligands attached to the bismuth. The intermolecular and intramolecular H/D kinetic isotope effects observed for the competitive oxidation of p-bromobenzyl alcohols indicate that the rate-determining step involves C-H bond cleavage. Several primary and secondary alcohols were oxidized efficiently under mild conditions by the combined use of newly developed organobismuth(V) oxidants and DBU.

Bismuth‐Mediated α‐Arylation of Acidic Diketones with ortho‐Substituted Boronic Acids

“…Consistent with known reactivity patterns, the addition of an unprotected indole, [62, 63] benzylamine, [64] benzyl alcohol, [65] or thiophenol [47, 66] led to a significant decrease in the yield of Bi V dibenzoate 3 d (step 1; compare entry a with entries b, d, e and j). In contrast, aldehydes, electrophilic alkyl halides, electron‐poor and electron‐rich alkenes, and acidic ketones are well tolerated in the same step (entries f–i, k).…”

Recent Progress in the Synthesis of Aryl Trifluoromethyl Ketones

“…然而, 该反应需要 3.7 equiv.的氧 化剂, 才能极大地缩短反应时间, 反应仅需 15 min, 并 能有效地提高反应的转化率. 随 后 , 氟 氧 代 硫 酸 铯 (CsSO 4 F) [10] 、 N-氧 铵 盐 (AcNH-TEMPO) [11] 、2-碘酰基苯甲酸(IBX) [12] 、有机高 价碘 [13] 、三芳基二氯化铋 [14,15] 2000 年, Bégué 课题组 [18] 报道了以当量的高碘酸钠 和空气为氧化剂, 利用钌配合物催化醇的氧化反应, 得 到了较高产率的三氟甲基酮化合物. 随后, Pedro 课题 组 [19] 报道了以氧气为氧化剂, 利用钴配合物催化 α-三 氟甲基-α-羟基羧酸的氧化脱羧反应.…”

Synthesis of Aryl Trifluoromethyl Ketones

“…One of the early examples was described by Linderman's group in 1987 for the synthesis of fluorinated ketones through oxidation of perfluoroalkylsubstituted carbinols using the Dess-Martin reagent. 40,41 Subsequently, various oxidants such as cesium fluoroxysulfate (CsSO 4 F), 42 the triarylbismuth dichloride-DBU binary system, 43,44 o-iodoxybenzoic acid, 45 Oxone ® (2KHSO 5 •KHSO 4 • K 2 SO 4 ), 46 and 4-acetylamino-2,2,6,6-tetramethylpiperidine-1-oxoammonium tetrafluoroborate 47 were utilized.…”