Covalently Bound Directing Phosphorus Groups

The high diastereoselectivity in favor of the anti product was almost independent of the nature of the rest R. A catalyst-substrate complex was identified wherein unfavorable steric interactions were minimized, which explained the 

BOP =(Benzotriazol-1-yloxy)tris (dimethylamino)phosphonium hexafluotophosphate (Rp)-o-DPPF= Q 

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Tervalent phosphorus acid derivatives (1) are compounds with three covalent bonds to phosphorus and at least one electronegative atom bound directly to the phosphorus atom. Such compounds are able to undergo a diversity of reactions since they are nucleophiles due to the lone pair on phosphorus and also electrophiles because of the presence of a leaving group X. They are generally reactive towards water and often easily oxidized. They are therefore mainly used as intermediates for the preparation of more stable phosphorus compounds, such as phosphine oxides, phosphates and phosphonates. 

How is ATP made No covalent intermediates have been identified, and isotopic exchange studies indicate a direct dehydration of ADP and P to form bound ATP.245 For the nucleophilic terminal phospho group of ADP to generate a high-energy linkage directly by attack on the phosphorus atom of P an OH ion must be eliminated (Eq. 18-13). This is not a probable reaction at pH 7, but it would be reasonable at low pH. Thus, one function of the oriented ATP... 

Scheme 2 Two potential reaction mechanisms for phosphatases or sulfatases are shown here using a phosphate ester. In (a), the phosphoryl group is transferred directly to a water molecule, which is typically bound to one or two metal ions if the substrate is made chiral at phosphorus, the stereochemical outcome is inversion. In (b), the phosphoryl group is first transferred to an enzymatic nucleophile E-POs " is a covalent phosphoenzyme intermediate. In a subsequent step, this intermediate is hydrolyzed. Since each step occurs with inversion of configuration at phosphorus, the net outcome is retention. The same principles apply to sulfuryl transfer. P, = inorganic phosphate.

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