Allylic phosphonates rearrangement

Janecki, T, and Bodalski, R., A convenient method for the synthesis of substituted 2-methoxycarbonyl-and 2-cyanoallylphosphonates. The allyl phosphite-allyl phosphonate rearrangement, Synthesis, 799, 1990. 

A-trityl-(l/ ,2S)-norephedrine (58), the corresponding allyl phosphonates 62a,b were obtained via the Arbusov rearrangement of 2-ethoxy-1,3,2-oxazaphospholidine 60. The absolute configuration of the major diastereomer, 62a was determined by X-ray as (2S1,45,51 ).The reaction of the major diastereomer of allyl phosphonates 61a and 62a with DBU afforded the corresponding vinylphosphonates 63a,b (Scheme 21) [48], Nucleophilic addition to these resulted in induction of chirality at the [1-position of the stereogenic phosphorus atom in the initially produced diastereomeric phosphonates 64 or 65 (Scheme 21) [48],... 

The use of NiCl2 catalysts in the rearrangement of allylic phosphites (and related compounds) to allylic phosphonic (or phosphinic) acids has already been reported (Organophosphorus Chemistry, 1988, 1, 144), and the same authors have now described the use of Ni(cyclooctadiene) catalysts in the presence of bistrimethylsilylacetamide in the reactions between allylic esters,or carbonates, and dialkyl phosphites, monoalkyl alkylphosphonates,or monoalkyl... 

An alternative access to allyl vinyl rearrangement systems was introduced by Gilbert [22e]. The condensation of diethyl(diazomethyl)phosphonate 147, the ketone 148, and a secondary allylamine 149 gave the allyl vinylamine 150, which could be activated (126) for rearrangement via N-methylation using dimethylsul-... 

Hayashi and Midorika (191) used a [3,3]-sigmatropic rearrangement of an allylic dithiocarbamate to stereospecifically generate -olefins (Scheme 81). Reduction of alkylated allylic phosphonates with lithium aluminium hydride by Kondo et al. (192) exclusively gave E-alkenes (Scheme 82). 

A nice application of this reaction for the synthesis of cyclic a-sulfanylphos-phonates 63 has been reported [42]. It involves a Rh(II)-catalyzed [2,3]-sigmatropic rearrangement and a ring-closing metathesis of the resulting a-(S-allyl) y,d-unsaturated phosphonates 62 (Scheme 16). However, the last step occurs with a low yield (19%) when R = H. 

The photo-Arbuzov rearrangement of allyl-, benzyl- and naphtylmethyl-phosphites (Scheme 13), first developed by Bentrude et al. [20], found applications in the preparation of phosphonates (70-90%) [38]. Arylphosphonates have been shown to act as protein tyrosine kinase inhibitors [39] or non-hy-drolyzable analogs of phosphorylated tyrosine residues [40]. 

The intermediate product 162, formed from the nudeophilic addition of 1,2-alle-nic phosphonate or 1,2-allenic phosphine oxide with allylic alcohol, would also undergo a Claisen rearrangement to form 2-oxo-5-alkenyl phosphonate or phosphine oxide 163 [85], The rearrangement is accelerated by the carbanionic nature of the intermediate 162. For the conjugate addition step, the reaction temperature is crucial since the reaction at 0 °C afforded mainly /i,y-unsaturated product whereas a,/8-unsaturated products were formed at 20 °C. 

The principally practicable route to allyl vinyl ethers by alkenation of allyl formates, has not yet been exploited in this context. In another approach, the nucleophilic addition of allylic alcohols to alkynic esters, one observes the exclusive formation of franr-enol ethers 2 the stereochemical information is lost, however, after the rearrangement, due to enolization of the formed formylacetic acid derivatives. On the other hand the nucleophilic addition of allyl alcohols to acceptor-substituted allenes like allenic sul-fones or phosphonates offers a novel route with fascinating potential. " Such systems that are readily... 

One of the photorearrangements studied in this laboratory is the conversion of allyl phosphites to the the corresponding phosphonates (74). Although this rearrangement occurs thermally at 2(X) (72), the photochemical process proceeds readily at room... 

Ohler, E.. and Zbiral. Ei.. Oxidative rearrangement of phosphorus containing tertiary allylic alcohols. Synthesis of (3-oxo-l-cycloalkenyl)phosphonates, -methylphosphonates, -methyldiphenylphosphine oxides and their epoxy derivatives. Synthesis, 357, 1991. 

Allylic rearrangements are observed when the esters 120 are treated with SOCI2 to give the (3-chloroalk-l-enyl)phosphonic esters but the similar treatment of the esters... 

Simple alkyl ethers are readily available by appropriate alkylation with alkyl halides and, of such ethers, the allyl ethers are of special interest ". Allyl ethers from slightly more complex hydroxy acids have been obtained as carbanions by the addition of allyloxy ions to dialkyl (l,2-alkadienyl)phosphonates (Scheme 36), when the main products were the separable ketones 202 (37%) and 203 (19%) formed by Claisen rearrangements within the mesomeric ion 201 ". ... 

The synthesis of Cbz-protected D-valine methyl ester (296) (Scheme 40) begins with addition of an organometallic reagent to the ester function of 282. The resulting phosphonate 290 undergoes a Wittig reaction with isobutyraldehyde to afford 291. Chelation-controlled reduction of the ketone with zinc borohydride furnishes the a /-alcohol 292 (98% de). A [3,3] rearrangement of trifluoroacetimidate 293 produces allylic amine 294. Elaboration of the olefin to an ester furnishes the D-valine derivative 296 with 85% ee [101]. 

The transformation of an MBH adduct into stereoselectively allyl phos-phonates was initially reported by Morita et al. and then Janecki and Bod-alski reported that MBH adducts 11 and 12 can react with dialkyl chlorophosphites in the presence of triethylamine to give the corresponding phosphonates 13, which underwent the Arbuzov rearrangement upon heating to produce 2-methoxycarbonylallylphosphonates 14 with high stereoselectivity (Z E =95 5) and 2-cyanoallylphosphonates 15 with moderate stereoselectivity (E Z= 60 40 75 25) in moderate to high yields (Scheme 3.5). 

ADPPO compound was obtained by the reaetion between triphenyl phosphine and allyl bromide aeeording to a Miehaelis-Arbuzov rearrangement, and the DAPPO eompound by a Williamson reaetion between an aromatic phosphine and 2 equivalents of allyl bromide. The phosphonated monomers were added separately in an epojqr aerylate resin eured by UV radiation in the presenee of a photoinitiator. 

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