Elie About-Jaudet

α-FUNCTIONAL CYCLOALKYLPHOSPHONATES I. SYNTHESIS

Abstract Cycloalkylphosphonates 2 of different sizes (from cyclopropyl to cycloheptyl) bearing various functional groups Z in a position were synthesized by bis-alkylation of α-functional methylphosphonates 1 and Ω-dibromoalkanes in presence of base. The choice of the basic system is determined by the nature of Z. With powerful electron-withdrawing groups, NaH-THF/DMSO (Method A, for Z=CN, SO2R) or liquid-solid phase transfer process [Method B, for Z=COOR, P(O) (OEt)2] proved to be the more suitable systems. For Z=aryl or SR, lithium diisopropylamide is required to achieve the deprotonation. A wide range of new phosphonates were obtained in high yields on preparative scale.

Phosphonates α-lithies agents de transfert fonctionnel. Preparation de phosphonates α-amides et d'amides α, β-insatures, α-substitues

Abstract Lithiated anions ( 9 ) or ( 10 ) of secondary or tertiary α -amidophosphonates are prepared either by reaction between an α-phosphonyl carbanion and an isocyanate or a carbamate (first strategy), or by condensation of an amide enolate with diethylchlorophosphate (second strategy). Acidic hydrolysis of ( 9 ) or ( 10 ) gives α-amidophosphonate ( 1 ) alkylated or not in the α -position. ( 9 ) and ( 10 ) react with aromatic or aliphatic aldehydes to produce α,β-unsatured secondary or tertiary amides ( 2 ).

α-Iithioalkylphosphonates as Functional Group Carriers. an in Situ Acrylic Ester Synthesis

Abstract Condensation of α -lithioalkylphosphonates with diethylcarbonate in the presence of LDA generates carbetoxy-alkylphoshonate anions which upon treatment at room temperature with aldehydes constitutes an in situ acrylic ester synthesis.

A Convenient Method for the Synthesis of bis-Trifluoroethyl Phosphonoacetates

Abstract bis-Trifluoroethyl phosphonoacetates were easily obtained by condensation of bis-trifluoroethyl alkylphosphonates with alkyl chloroformates in the presence of 2 equivalents of lithium hexamethyldisilazane (LiHMDS).

Sigmatropic (2,3]-Wittig rearrangement of α-allylic-heterosubstituted methylphosphonates. Part 31 : High diastereoselectivity in the rearrangement of anion of dimenthyl allyloxymethylphosphonate

Abstract A diastereoselectivity up to 90% was achieved in the title rearrangement of lithiated allyloxymethylphosphonates, by using the cheaply available chiral dimenthylphosphonyl ester group as stereo-directing auxiliary. The absolute configuration of the newly formed chiral center was assigned by usual chemical conversions.

Sigmatropic [2,3]-wittig rearrangement of α-allylic-heterosubstituted methylphosphonates. Part 2: Rearrangement in the nitrogen series

Abstract Whereas the lithiated carbanion derived from the diethyl ( N -allyl, N -phenyl)-amino methylphosphonate 1 failed to undergo the [2,3]-Wittig shift, ammonium salts resulting from the quaternization of diisopropyl ( N,N -diethyl)-aminomethylphosphonate 8 with allylic bromides, were conveniently rearranged into the α-( N,N -diethylamino)-alkenylphosphonates 11 , in the presence of t -BuOK, in DMF, at −40°C.

A Simple and Efficient Synthesis of 2-Substituted 3-Diethylphosphono 5-Methylfurans

Abstract An efficient carbanionic synthesis of the phosphonic dicarbonylated compounds 2 was achieved and used as key intermediates in the synthesis of the phosphonic furans 4 by acid-induced Paal-Knorr cyclization reaction.

A Convenient (E)-Stereoselective Synthesis of Alkenylphosphonates

Abstract Diethyl (E)-alkenylphosphonates have been prepared stereoselectively by dehydration of the corresponding β-hydroxyphosphonates using DCC/CuCl2 in refluxing toluene. Starting β-hydroxyphosphonates were obtained in high yield from diethyl methylphosphonate.

A Convenient Synthesis of Diethyl 2,4-Dioxoalkylphosphonates

Abstract Diethyl 2,4-dioxoalkylphosphonates are prepared in excellent yields by Claisen condensation of the dianion of diethyl 2-oxoalkylphosphonates with ethyl esters or acyl chlorides in the presence of one equivalent of lithium diisopropylamide (LDA).

A remarkable accelerating effect of iodide ions in the photostimulated phosphonylation of bromoaromatic compounds

Abstract We find that 1 equiv. of NaI greatly accelerates the photostimulated substitution (S RN 1 mechanism) of bromobenzene, bromotoluenes and bromopyridines by diethylphosphite ion, in acetonitrile/tetrahydrofuran mixtures. Consequently, bromoaromatic compounds are suitable for preparative use.