Paper
SUBSTITUENT EFFECTS ON PHOSPHONATION OF γ-CHLOROPROPYL ARYL KETONES WITH TRIETHYL PHOSPHITE
Published Dec 1, 1997 · Jen-Wen Yu, C. Shih, Steve K. Huang
Phosphorus Sulfur and Silicon and The Related Elements
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Abstract
Abstract Phosphonation of γ-chloropropyl aryl ketones 1 with triethyl phosphite yielded oxycyclopentyl phosphonates 2 and γ-ketophosphonates 3. Formation of 2 was greatly facilitated by the presence of electron-releasing p-substituents on the phenyl group, particularly the methoxy group, which may delocalize the electrons of the methoxy oxygen towards carbonyl oxygen through resonance effect. The linear Hammett plots for 2 showed negative p value of −2.33 (r = 0.993) for the solution with TEP/1 ratio of 4.5 and −3.09 (r = 0.999) for TEP/1 ratio of 1.5. In contrast, the formation of 3 occurred through a carbonyl group-assisted reaction pathway and the Hammett plot with a positive ρ value of 1.33 (r = 0.986) indicated that the reaction was accelerated by the presence of deactivating halogen as substituents, through the inductive effect. The direct replacement of halogen via SN2 mechanism displayed an expected rate constant of 0.67 × 10−6 Lmol−1s−1, and the formation of 3 (Y = H) was observed to occur at the...
Substituent effects on phosphonation of -chloropropyl aryl ketones with triethyl phosphite reveal that electron-releasing p-substituents facilitate formation of 2 and deactivating halogen accelerates formation of 3.
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