The reaction of terminal alkynes with PhI(OAc)2: a convenient procedure for the preparation of α-acyloxy ketones

Iodobenzene Dicarboxylates as Transferrable Oxygen Sources: Synthesis of α-Oxygenated Ketones from Terminal Aryl Alkynes

“…In the control experiments, we found that external HOAc (Table 1, Entry 8) had almost no effect on the reaction yield. On the basis of the results described above, and along with the previous work by Muñiz, [11,14] Hou, [12] and Ochiai, [20] a plausible mechanism for the conversion of alkynes into α-oxygenated ketones is proposed and depicted in Scheme 4. Reaction of the alkyne with PhI(OCOR) 2 2 O, the iodonium ylide III is formed, and further electrophilic addition of (RCO) 2 O to III gives intermediate IV.…”

“…[9,10] However, the reaction of iodobenzene diacetate with alkynes is less well-documented. [11] In 2009, Hou and co-workers [12] reported the reaction of alkynes and iodobenzene diacetate, giving rise to useful α-acetoxy ketones. In this literature, the acetic acid was used as solvent, and the temperature of reaction was at 70 ℃.…”

“…The modified conditions developed by our group appear to be much milder and thus more attractive and practical relative to previous research. [11][12][13] Through detailed study, we found that various α-acyloxy ketones can be obtained by the reaction of alkynes with a series of iodobenzene dicarboxylates [PhI(OCOR) 2 , R＝Me, t-Bu, and Ph]. Moreover, when bis(trifluoroacetoxy)iodobenzene (PIFA) was used, α-hydroxy ketones were obtained in high to excellent yields.…”

Cu–iminopyridine complexes as catalysts for carbene and nitrene transfer reactions

“…Such a reaction has been already described in the literature and is reported to take place without a catalyst. [22] Nevertheless, the presence of CuCl(L1)(PPh 3 ) allows the reaction to proceed to a certain extent even at rt, which is not the case under metal-free conditions (9% yield after 12 h). [22] More work is needed here in order to assess the catalytic potential of copper-based catalytic systems in this kind of transformation.…”

Metal-free syntheses of oxazoles and their analogues based on λ3-iodane-mediated cycloisomerization/functionalization reactions or [2+2+1] cycloaddition type reactions

“…The iodonium ylides like Int-D has been proposed as a key intermediate in the PIDA-mediated oxidation of terminal alkyne compounds to α-acetoxy ketones. 23 Also, alkylideneoxazoline has been known to be isomerized to oxazole by acid. 24 Finally, the substitution of phenyliodonium group of Int-E by AcOH and/or the reductive elimination of PhI 25,26 would give the target oxazoles 2.…”