Phosphonamidates rearrangement

In the presence of sodium methoxide, alkyl N-alkyl-(1-chloroalkyl)phosphonamidates rearrange to (1-aminoalkyl)-phosphonates ( a reaction previously observed) together with phosphoramidates-the latter a new feature of mechanistic significance.The use of methoxide did lead, however, to complications due to the further degradation of the products, and the use of benzyltrlmethylammonium methoxide was found to be more satisfactory. This brought about the conversion of... 

The rearrangement of the /V-phosphinoyl-O-sulfonylhydroxylarninc (268) (with 57% enrichment with one 180 atom in the SO2 group) to the sulfonamide (269) (43.7% enriched with one 180 atom) occurs with Bu NH2 in dichloromethane via the phosphonamidic-sulfonic anhydride intermediate (270).245 The rearrangement of the O-phosphinoyl compound (271) with /-butoxide gives the phosphonamidic-phosphinic... 

Optically active phosphonamidates have been used for chiral auxiliary based Claisen rearrangements (see Section 1.6.3.1.1.5.2.2. p 3508)105 I06. 

In contrast to the rearrangement of phosphonamidates, the results obtained with phos-phonamides are poor. The rearrangement of chiral versions of different phosphonamide structural classes, e.g., 9,11,13, 15, and 18, show a high internal induction, but sluggish asymmetric induction. Models feature a planar carbanion and chelation between the phosphonyl and the ether-type oxygen, with insufficient differentiation for asymmetric induction provided by the tV-ligands634. 

Assorted anions. These are generated by deprotonation of allylic halides," chloromethylphosphonic esters, conjugated hydrazones, chiral carbamates,unsaturated a-aminonitriles, phosphonamides," and sulfonamides. The dianions derived from tu-haloalkanecarboxylic acids cyclize, and this reaction forms the basis of a synthesis of V-Boc cyclic imino acids. The conjugate bases of 2-(arylmethoxy)-methyl-2-oxazolines are unstable as [2,3]sigmatropic rearrangement takes place even at — 75°C. 

In the above discussion, it was presumed that one of the intermediates involved in the photo-Curtius rearrangement is indeed a phosphinoyl nitrene. Although the formation of the alkyl phosphonamidic esters constitutes one line of evidence for the intermediacy of... 

Denmark has also investigated the carbanion accelerated Claisen rearrangement of allyl vinyl ethers with cydic phosphonamides as carbanion-stabihzing groups [78], because phosphonamide allyl anion is well established and has potential for chiral modification. 

A retro-1,5-Brook rearrangement may have been the source of the unusual silane 173, formed unexpectedly in the course of Evans s studies on phosphonamide-stabilized carbanions. Metalation at the A-methyl position would lead to the rearrangement of 172 across a unique heteroatom-containing tether. ... 

Phosphorus analogs of hydroxamic acids, prepared fromphos-phinic chlorides and Ai,0-bis(trimethylsilyl)hydroxylamine, tend to be unstable. The stable O-sulfonyl derivatives of the phos-phinoylhydroxylamines undergo base-induced, Lossen-type rearrangement to phosphonamidates by aryl group migration from P to N (eq 4). ... 

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