Triphenylphosphine-mediated olefination of aldehydes with (Z)-(2-acetoxyalk-1-enyl)phenyl-λ3-iodanes: generation and reaction of (2-oxoalkyl)phenyl-λ3-iodanes

A New Route for Generation of α-λ3-Iodanyl Ketones via Ester Exchange of (Z)-(β-Acetoxyvinyl)-λ3-iodanes: Their Nucleophilic Substitutions with Halides and Sulfur and Phosphorus Nucleophiles

“…The formation of phosphonium ylide 28 is compatible with the reported acidity of acetonyl(triphenyl)phosphonium salt 22d (R = Me, p K a = 6.6), more acidic than Et 3 NHBF 4 . We have reported that, after treatment of 2 with triethylamine in the presence of triphenylphosphine in MeOH at room temperature, addition of an aldehyde to the reaction mixture and then heating at 60 °C resulted in the formation of α,β-unsaturated ketones with high trans selectivity 9 …”

“…We envisioned that generation of the monocarbonyl iodonium ylides 3 in the presence of an appropriate proton source with similar acidity (p K a = 12) makes it possible to protonate the iodonium ylides 3 , producing α-λ 3 -iodanyl ketones 1 (R 2 = H). We now report a method for in situ generation of α-λ 3 -iodanyl ketones 1 from ( Z )-(2-acetoxyvinyl)(phenyl)-λ 3 -iodanes 2 (X = BF 4 ) via ester exchange reaction of the β-acetoxy group, and their nucleophilic substitutions with halides and sulfur and phosphorus nucleophiles …”

Advances in Synthetic Applications of Hypervalent Iodine Compounds

“…Several useful reactions of unstable monocarbonyl iodonium ylides, which were generated from ( Z )-(2-acetoxyvinyl)­iodonium salts and lithium alkoxides or triethylamine via the ester exchange reaction, have been reported by Ochiai and co-workers. − For example, the in situ reactions of aldehydes or imines afford the corresponding epoxides or aziridines. , Miyamoto and co-workers have investigated reactions of β-butoxycarbonyliodonium ylides, Darzen reagent analogues, which were prepared by the ester exchange reaction of β-butoxy-β-acyloxyvinyl-λ 3 -iodane 461 with lithium bases . The iodonium ylide generated in situ from 461 cleanly undergoes Darzen’s condensation with aromatic aldehydes 462 to selectively give the trans epoxyester 463 (Scheme ).…”

Recent Developments in the Chemistry of Polyvalent Iodine Compounds

“…Several new, potentially important classes of iodonium ylides have been prepared and investigated in the last 5 years. − Spyroudis and Varvoglis reported the synthesis of a new class of stable zwitterionic aryliodonium compounds 589 from 2-amino-1,4-naphthoquinone 588 and [hydroxy(tosyloxy)iodo]arenes (eq 244). −

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“…The treatment of iodonium salts 594 with triethylamine in methanol in the presence of triphenylphosphine and aldehydes results in Wittig olefination (eq 250), which involves the intermediacy of monocarbonyl iodonium ylides 596 and their subsequent conversion to the respective phosphonium ylides upon the in situ reaction with Ph 3 P …”