Oxidative rearrangements of arylalkenes with [hydroxy(tosyloxy)iodo]benzene in 95% methanol: a general, regiospecific synthesis of α-aryl ketones

Asymmetric total synthesis of (−)-lingzhiol via a Rh-catalysed [3+2] cycloaddition

“…6). Treatment of commercially available 5,8-dimethoxy-3,4-dihydronaphthalen-1(2H)-one (28) with a mixture of Ph 3 PCH 3 Br and potassium bis(trimethylsilyl)amide (KHMDS) in tetrahydrofuran (THF) resulted in the formation of the expected olefin in 98% yield, which was subsequently reacted with Koser's reagent 65 in the presence of p-TSA in MeCN to give the benzoannulenone 29 in 95% yield via a ring-expansion reaction. Compound 29 was initially reacted with formyl aldehyde under a variety of different conditions.…”

Transition Metal-Catalyzed Direct Arylation of Substrates with Activated sp3-Hybridized C−H Bonds and Some of Their Synthetic Equivalents with Aryl Halides and Pseudohalides

“…Moreover, many of these procedures do not involve arylation of ketones, but instead of their less readily available derivatives including R-haloketones 28d,30,34 or silyl enol ethers. 28c,31, 33a,d Other methods to prepare R-arylated ketones rely on intramolecular nucleophilic addition of silyl enol ethers of ketones to electron-transfer generated arene radical cations, 36 regiospecific reaction of arylalkenes with [hydroxy(tosyloxy)iodo]benzene, 37 direct nucleophilic acylation of oquinone methides, 38 arylation of lithium enolates of cycloalkanones with diphenyliodonium triflate in the presence of stoichiometric quantities of CuCN, 39 and reaction of isopropenyl acetate with aryldiazonium tetrafluoroborates in aqueous acetone in the presence of KOAc. 40 The latter methodology was applied to the multigram scale preparation of 1-(3-bromo-4-methylphenyl)propan-2-one.…”

Facile Oxidative Rearrangements Using Hypervalent Iodine Reagents

“…The combination of hypervalent iodine reagents and boron trifluoride diethyl etherate, BF 3 ⋅Et 2 O, has already been studied,9 and, here, a weak activation was observed, and rearranged product 2 a was isolated in only 18 % yield together with a different rearranged product 3 a , which was obtained in 67 % yield (Table 1, Entry 3). Rearrangement products such as 3 a have already been reported using hypervalent iodine reagents 2b, 10. Rearranged cyclic product 2 a was not observed by using a Brønsted acid such as camphorsulfonic acid and only product 3 a was formed (Table 1, Entry 5).…”