Phosphorous acid amides phosphoramidates

In 2006, Yamamoto and Nakashima picked np on this and designed a chiral A -triflyl phosphoramide as a stronger Brpnsted acid catalyst than the phosphoric acids based on this concept. In their seminal report, they disclosed the preparation of new chiral BINOL-derived A -triflyl phosphoramides and their application to the asymmetric Diels-Alder (DA) reaction of a,p-unsaturated ketones with sily-loxydienes [83], As depicted in Scheme 59, chiral A-triflyl phosphoramides of the general type 4 are readily synthesized from the corresponding optically active 3,3 -substituted BINOL derivatives 142 through a phosphorylation/amidation route. 

Phosphoramidous fluorides, 13 383-389 Phosphoranes, 16 47 cage compounds, 30 246 as propellanes, 33 268 Phosphorescence, 19 68 Phosphoric acid ester amides, reaction with hexafluoroacetone, 30 237 Phosphoric acids, condensed, properties of, 5 220... 

Although carboxylic as well as phosphoric esters are widely utilized in nature, phosphoric amides do not parallel their carboxylic counterpartners as the widespread biological struc -tures. This is most likely due to the low stability of the P(0)-N bond under acidic conditions a property resulting from the different bonding at the phosphoramidate function, relative to the carboxylic system. 

Phosphorylation. Chambers et al. found the reagent useful for the preparation of nucleoside diphosphoric acids (3, R —adenine, uracil, etc.). A nucleotide (I) is converted into the 5 -phosphoramidate (2) by reaction with ammonia and dicyclo-hexylcarbodiimide (DCC), and the amidate (2) is treated with dioxane diphosphate in o-chlorophenol (3 hrs..0 ). The diphosphoric acid (3) is precipitated with petroleum ether and purified as the ammonium salt. Yields are around 90%, whereas when 8.5% phosphoric add was used yields were in the order of 50-60%. However, anhydrous... 

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