New synthesis of wittig-horner reagents and its reaction

Abstract

A convenient synthesis of α-heteroatom substituted phosphonates and β-keto phosphonates has been studied. Treatment of diethyl trimethylsilyl phosphite (DTSP) with arylaldehyde acetals and its derivatives such as arylaldehyde thioacetals, orthoformates in the presence of Lewis acid, respectively, gives the corresponding phosphonates in high yields under mild conditions. Titanium (IV) chloride catalyzed addition of diethyl trimethylsilyl phosphite (DTSP) to β-nitrostyrenes afforded α-phosphoryl nitronates which on treatment with low valent titanium in situ generated from titanium (IV) and zinc, was smoothly converted to 1-aryl-1-cyanomethanephosphonates in good yields. β-Keto phosphonates was obtained by the reaction of DTSP with nitro olefin in presence of titanium (IV) chloride in moderate yields. And, reaction of triethyl phosphite with silyl enol ether in the presence of iodosobenzene and boron trifluoride etherate afforded the β-keto phosphonates in good yields. Wittig-Horner reaction of 1-aryl-1-cyanomethanephosphonates with aldehyde has been studied.