Staudinger-type reactions

Fig. 40 Formation of (3-lactams via asymmetric Staudinger-type reactions, catalyzed by 64c...

An efficient synthesis of tetrahydrofuran-derived spiro-p-lactams has been reported to be performed by a Staudinger-type reaction of either 2- or 3-tetra-hydrofuroyl chloride with imines [66]. The reaction was carried out by adding Et3N... 

The group of Podlech has reported that trans-substituted (3-lactams (dr 70 30) can be prepared treating an Fmoc-protected leucine-derived diazoketone with a benzylidene-protected glycine ester in a photochemically induced Staudinger-type reaction [173]. Separation of the isomers, deprotection, and attachment of Fmoc-proline using the pentafluorphenyl ester activation protocol yielded the protected peptidomimetic in 93% yield, (Scheme 74). Deprotection and amidation resulted in formation of the /ram-substituted (3-lactam. 

Related compounds of the type (Me2N)2P(Q)-N=P (NMe2)3 have been obtained from P(NMe2)3 with (Me2N)2P(X)N3 in a Staudinger type reaction. ... 

In a Staudinger-type reaction, the azido group was converted into the corresponding phosphoryl imine which after hydrolysis gave the desired amino nucleosides. The starting azido nucleosides were used either with protected or unprotected bases with good results. Filtration of the crude mixture led to pure products in in excellent yields (89-100%). 

One-step conversion of A-(o)-azidoalkyl)lactams to bicychc amidines, avoiding the protection-deprotection sequence on the amine part, is explored by applying the intramolecular Staudinger-type reaction [26]. Oxalyl chloride [(COCl)2] and bromide [(COBr)2] are found to be effective trigger reagents and the corresponding bicyclic amidines are produced in high yield (Table 3.1). 

An unusual iminophosphenium cation is produced in a Staudinger-type reaction with phenyl azide [11],... 

Phosphoramidate-linked dinucleotide analogues 79 have been obtained by the reaction of 5 -azido-nucleosides with the dimethyl sugar phosphite in a Staudinger-type reaction followed by in situ Michaelis-Arbusov reaction. Regioisomers with oxygen and nitrogen reversed were similarly obtained fiom an AZT derivative. ... 

There have been two reports of the synthesis of di- and oligonucleotides with P-NH-5 -phosphoramidate intemucleotide links 134.135 in one approach 135 a Staudinger-type reaction is used to form the link (Scheme 15). Another paper has reported the synthesis of building blocks for 5 -amino- and 5 -mercapto-ollgodeoxy nucleotides. 136... 

Glycosides (19) of 2-acetamido-2-deo) -D-glucose, including disaccharides, can be obtained via Staudinger-type reaction (Scheme 8) of the iodo-azide (20),... 

Scheme 16.12 Three-component Staudinger-type reaction with ji-glycosyl azide 4 stereose-lectively leads to the ji-glycosyl amides 48. a-Clycosyl amides can only be obtained from a-glycosyl azide 49 with strong acylating agents to prevent complete anomerization of the Intermediate lmlnophosphorane °...

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