Categories: C=C Bond Formation >
Synthesis of alkenes by syn-eliminations
The use of TMSO-/Bu4N+ as Lewis base activator enables highly stereoselective aza-Peterson olefinations from bench-stable α,α-bis(trimethylsilyl)toluene reagents and N-substituted imines. N-t-butanesulfinyl imines were utilized for the synthesis of Z-stilbenes with excellent selectivities, while N-aryl imines generated E-stilbenes under identical reaction conditions via syn-elimination of an in situ formed hypervalent silicate.
M. Das, D. F. O'Shea, Org. Lett., 2016, 18, 336-339.
Pd(PPh3)4-catalyzed isomerization of methylenecyclopropanes (MCPs) proceeds smoothly at 80°C in acetic acid and toluene to give 1-substituted or 1,1-disubstituted dienes in good to excellent yields. The mechanism is discussed.
M. Shi, B.-Y. Wang, J.-W. Huang, J. Org. Chem., 2005, 70, 5606-5610.
Samarium diiodide promotes a photoinduced metalation of nonactivated C-Cl bonds of O-acetyl chlorohydrins and a β-elimination which affords alkenes with total or high stereoselectivity.
J. M. Concellon, H. Rodriguez-Solla, C. Simal, M. Huerta, Org. Lett., 2005, 7, 5833-5835.
Highly stereoselective syntheses of (E)-α,β-dehydroamino acids and (E)-α,β-dehydropeptides have been achieved in good yields by stereospecific dehydration of threo-β-hydroxy-α-amino acid derivatives using 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide (EDC) and CuCl2.
H. Sai, T. Ogiku, H. Ohmizu, Synthesis, 2003, 201-204.