Phosphinic amides cyclization

Novel cyclic A-(co-haloalkyl)phosphinic amides of the general type 111 cyclize when treated with and the hydrogenphosphonic diamides 112 have also been alkylat-... 

The oxime from (4-chloro-l-oxobutyl)phosphonic acid has been cyclized to Pro ". An unusual rearrangement based on valence expansion of phosphorus is of interest the treatment of an (oxoalkyl)phosphonic oxime with Ph2PCl initially yields the phosphorus(III) derivative, but this rearranges spontaneously to give a phosphinic amide derivative 300, reduction of which then affords the [(V-diphenylphosphinoylamino)alkyl]phosphonic acid, readily hydrolysable under acid conditions to the free (aminoalkyl)phosphonic diester (Scheme 34)" ". 

The reductive cyclization of the 2-nitrodihydrocinnamoyl group has found application for the protection of alcohols and amines using sodium phosphinate or cyclohexene as the hydrogen donor. - The hydrogen transfer reduction of both esters and amides regenerates the alcohols or amines under mild conditions (equation 12). 

Like the cycloisomerization of propargylamine amides, allylamine amides such as 181 undergo 5-i 3cti-cyclization in NaOH to give phosphine oxide-substituted oxazoles 182 (Equation 11) <2004T8937>. 

Ni(cod)2 f eacts with a, 3-unsaturated amides in the presence of PCy3 to give an azan-ickelacyclic compound (eq (32)) [41]. A similar complex has been synthesized by the co-cyclization of propylene and phenyl isocyanate with a nickel(O) phosphine complex (eq(33))[42j. 

Diarylamines and o-dihaloarenes condense to give A -arylcarbazoles. " Exposure of o-bromobenzamides to Pd(OAc)2, CS2CO3 and a phosphine leads to debiominative coupling and cyclization with elimination of one amide unit, to give phenanthridinones. ... 

Access to bicyclic enones from 1,6-enynes by the Pauson-Khand method is rendered enantioselective by installing a chiral t-butylsulfinyl group at C-1. Cyclization of a-benzylidene-aroylacetamides to furnish 3-arylindanones is subject to 1,5-asymmetric induction when the amide moiety is derived from a bulky 4-substitulted oxazolidin-2-one. Chiral ligands for the Pauson-Khand reaction have also been studied. Phosphine-borane (111) derived from (-l-)-pulegone is an example. 

Aryl iodides are more reactive towards oxidative addition than aryl bromides, and a selective Heck coupling (without phosphine ligands) with an unsaturated side chain left the bromide in place. A second Heck reaction of this bromide with an allylic alcohol was used to introduce a second side chain. Cyclization of the amide on to the allylic alcohol was achieved with palladium catalysis, not as might have been expected with palladium(O) but instead with palladium(ll), to produce the seven-membered ring. Finally, the conjugated double bond was reduced and the sulfonamide removed under photolytic conditions. 

The exo-selective gold-catalyzed cyclization of alkenyl carbamates, amides, or ammonium salts affords the corresponding pyrrolidine or piperidine derivatives. Here, cationic gold(I) catalysts bearing sterically hindered, electron-rich phosphine ligands such as P(r-Bu)2(o-biphenyl) were much more reactive than PhsPAuOTf... 

Ortho C-H Bond Activation Regioselective Oxidative Cycloaddition of Aromatic Amides to Alkynes. Cyclometalation reactions with nickel phosphine COD complexes used an amido nitrogen atom as the coordinating atom. The insertion and cyclization with alkynes is then proposed to proceed via the cyclometalation nickel intermediate as an active center to give the six-membered isoquinolone derivatives shown in Eq. (6.6). In 2013, Chatani et al. [22] also reported on these chelation-assisted transformations in details as the review articles. 

When acid chlorides were used instead of cumulenes in the reaction with o-iodoanilines 3 and carbon monoxide (20atm), 2-substituted-4H-3,l-benzoxazin-4-ones 8 were obtained in good to excellent yields, also in the absence of a phosphine ligand [23]. The reaction is believed to proceed via in situ amide formation from o-iodoaniline and acid chloride, followed by oxidative addition to Pd(0), CO insertion, and intramolecular cyclization (Scheme 13.3). 

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