Free Radical-Mediated Ketone Synthesis from Alkyl Iodides via Sequential Radical Acylation Approach

Chemistry of β-(Acyloxy)alkyl and β-(Phosphatoxy)alkyl Radicals and Related Species: Radical and Radical Ionic Migrations and Fragmentations of Carbon−Oxygen Bonds

“…No correlation was found with any of the σ • scales examined. The reaction coefficient of 2.1 versus σ p is very high for a radical reaction and strongly supports the notion that the (phosphatoxy)alkyl migration proceeds via transition states with substantial polar character, polarized in the way shown To gain an insight into the extent of polarization of the acyloxy shift, Beckwith and Duggan determined the rates of rearrangement of three p-substituted phenylpropyl butyrate derived radicals (438-440) and the related 441, generated from the corresponding bromides, by means of the stannane clock method ( Table 2, entries [16][17][18][19][20][21][22][23][24]. 164 At 75°C in benzene, a Hammett correlation with the substituent constant σ p + was obtained, giving a reaction coefficient of F ) -0.71.…”

“…Solvent effects on the rearrangement rate of the unsubstituted phenylbutanoate radical (438) were also examined. The results of experiments with six solvents that spanned a broad spectrum of polarities showed a clear dependence of the ester migration rate on solvent polarity ( Table 2, entries [16][17][18][19][20][21]. Correlation of the rates with the solvent polarity parameter E T 173 gave a slope of 0.024, again indicating a mild but discernible polarization in the transition state for the butyrate shift.…”

Free‐Radical‐Mediated Multicomponent Coupling Reactions

“…Sulfonyl oxime ethers function as efficient radical C1 acceptors [45]. The instance in Scheme 6.26, in which a bissulfonyl oxime ether is used as a radical C1 acceptor, showcases the strategic aspect of this unique method for the synthesis of unsymmetrical ketones.…”

Synthesis of 1‐Silabicyclo[4.4.0]dec‐5‐en‐4‐ones: A Model of the A and B Rings of 10‐Silatestosterone

“…Migration of the carboncarbon double bond under basic conditions followed by neutralization afforded the expected ketones 24a and 24b, which were isolated in medium-to-good yields after silica gel chromatography (Scheme 14). and that of the α-hydrogen of 4,4-dimethyl-4-silacyclohex-2-en-1-one (25) [37] with those of the carbon analogues 26a, [38] 26b, [39] and 27 [40] shows the silicon atom exerts a similar downfield effect on these protons ( Figure 4 and Table 1). …”