Phosphonate-containing vinyl ethers

Dialkyl Phosphonate-Containing Vinyl Ether Monomers... 

The phosphonates (124), prepared from diazoalkanephosphonates by rhodium catalysed O-H insertion, undergo olefination to provide a synthesis of cyclic vinyl ethers (125).64 l-(Cyclopent-l-enylcarbonyl)vinyl-phophonates (126) have been used to synthesize fused ring systems containing two or three five-membered rings. The conversion of (126) into the aldehyde (127) followed by intramolecular olefinations leads ultimately to tricyclo[6.3.0.03.7]undecenone derivatives, e.g. (128).65... 

More recently, Souzy et al. synthesized a fluorinated vinyl ether-containing phosphonate moiety, i.e. dimethyl 4-[(a,p,p-trifluorovinyl)o gr]-phenylphosphonate, from a Michaelis-Arhuzov reaction in the presence of nickel(II) chloride as Lewis acid at 110 °C. Nevertheless, the reaction yield remains low (Scheme 3.6). 

This technique was thus applied by Iftene et al. for the synthesis of dimethyl 2-(vinylo>q )ethylphosphonate monomers (Scheme 3.9). Prior to the transetherification of the vinyl ether, a series of phosphonate-containing hydroxyl... 

When performed in ether at —70 °C containing HCl, the reaction between triethyl phosphite and either chloral or bromoacetone affords higher yields of the a-hydroxyphosphonates (34), relative to vinyl phosphate, than are normally obtained. The rate-determining step in the formation of the phosphonate (35) from chloroacetone and dimethyl hydrogen phosphonate appears to be the tautomerism of dialkyl phosphonate to phosphite. ... 

Enantioselective total synthesis of ((47J,5iS)-5-Amino-4-(2,4,5-tri-fluorophenyl) cyclohex- l-enyl)-(3-(trifluoromethyl)-5,6-dihydro-[l, 2,4]tri-azolo[4,3-a]pyrazin-7(877)-yl)methanone ABT-341 (708), a DPP4 (dipeptidyl peptidase IV) inhibitor, has been completed in diphenylprolinol silyl ether (707), in the one-pot, multicomponent, reaction of nitroalkene (704), acetaldehyde (703), vinyl phosphonate (706) and amine (705) (Scheme 178) A novel, catalytic, asymmetric Michael addition of azomethine ylide (710) with p-substituted tetraethyl alkyhdene bisphosphates (709) has been realised in the presence of a chiral copper(I)/TF-Bipham-Phos (712) complex. This system provided enantioenriched unnatural i -amino acid derivatives (711) containing gem-bisphosphonates in high yields with... 

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