52908-82-4Relevant academic research and scientific papers
C-H oxygenation at tertiary carbon centers using iodine oxidant
Kiyokawa, Kensuke,Ito, Ryo,Takemoto, Kenta,Minakata, Satoshi
supporting information, p. 7609 - 7612 (2018/07/15)
An oxidation system in which iodic acid (HIO3) is used as an oxidant in the presence of N-hydroxyphthalimide (NHPI) permitted the selective hydroxylation of tertiary C-H bonds and the lactonization of carboxylic acids containing a tertiary carbon center. These reactions are operationally simple and proceed under metal-free conditions using commercially available reagents, thus offering an ideal tool for the efficient oxidation of C-H bonds at tertiary carbon centers.
Synthesis of Lactones via C-H Functionalization of Nonactivated C(sp3)-H Bonds
Richers, Johannes,Heilmann, Michael,Drees, Markus,Tiefenbacher, Konrad
, p. 6472 - 6475 (2016/12/23)
An electron-deficient amide is utilized as a directing group to functionalize nonactivated C(sp3)-H bonds through radical 1,5-hydrogen abstraction. The γ-bromoamides formed are subsequently converted to γ-lactones under mild conditions. The method described is not limited to tertiary and secondary positions but also allows functionalization of primary nonactivated sp3-hybridized positions in a one-pot sequence. In addition, the broad functional group tolerance renders this method suitable for the late-stage introduction of γ-lactones into complex carbon frameworks.
Electroreductive hydrocoupling of activated olefins with ketones or aldehydes in the presence of trimethylchlorosilane
Shono, Tatsuya,Ohmizu, Hiroshi,Kawakami, Souta,Sugiyama, Hiroshi
, p. 5029 - 5032 (2007/10/02)
Electroreductive crossed hydrocoupling of α,β-unsaturated esters with aldehydes or ketones in the presence of trimethylchlorosilane afforded γ-lactones in good yields. Similarly, α,β-unsaturated nitriles gave γ-hydroxynitriles in high yields.
Three-Carbon Annelations. Regiocontrolled Reactivity of Trimethylsilyl- and Ethoxyethyl-Protected Cyanohydrins. Versatile Homoenolate and Acyl Anion Equivalents
Jacobson, Richard M.,Lahm, George P.,Clader, John W.
, p. 395 - 405 (2007/10/02)
The trimethylsilyl- (2) and ethoxyethyl- (4) protected cyanohydrins of α,β-unsaturated aldehydes are utilized as three-carbon annelation reagents.Metalated reagent 2 displays exclusive α reactivity with aldehydes and ketones at -78 deg C.Metalated reagent 4 displays exclusive α reactivity at -78 deg C and exclusive γ reactivity at 0 deg C.Reagent 4 thus allows for complete regiocontrol in its addition to aldehydes and ketones which permits selective addition of either a homoenolate or an acyl anion equivalent.Metalation of the α product 11 at -78 deg C with subsequent warming to 0 deg C produces exclusively the γ product, confirming the reversible nature of the addition to the carbonyl.The derived α '-trimethylsiloxy enones 17 (R3=Me3Si), α '-hydroxy enones 17 (R3=H), α '-acetoxyenones 17 (R3=Ac), and γ-lactones 10 are useful cyclopentenone precursors.Treatment of 17 with p-TsOH in toluene at reflux produces cyclopentenones.The reaction proceeds via the postulated intermediacy of a pentadienyl cation 15 which undergoes in situ electrocyclic ring closure.
