Phosphate esters as “tunable” reagents in organic synthesis

Abstract

The essential role phosphates have in biochemistry has no parallel in man-made chemistry, where the poor reactivity of these esters towards nucleophilic substitution makes more reactive substrates such as halides and sulfonates preferred. Nevertheless, phosphates are acquiring an increasing role in organic synthesis as long as new activation modes become available. These include metal catalysis and photochemistry (the latter effective with benzyl and aryl derivatives) that may turn the present limitation into a promising opportunity by devising convenient tunable reactions.

Regio‐ and Stereochemical Studies on the Nitroso‐Diels–Alder Reaction with 1,2‐Disubstituted Dienes

“…The same strategy was applied for the synthesis of the enol phosphate 20, an electron-poor analogue to the silyl enol ether. [23,24] Deprotonation of ketone 15 and treatment of the corresponding enolate with diethylchlorophosphate gave 18 as a pure Z isomer. Here also prolonged reaction times or the use of excess reagents resulted in b-elimination Scheme 2.…”

LiI/TBHP Mediated Oxidative Cross‐Coupling of P(O)–H Compounds with Phenols and Various Nucleophiles: Direct Access to the Synthesis of Organophosphates

“…[14] Moreover, Phosphate esters are tunable reagents and functional groups in organic synthesis. [7] Further, they have also been widely exploited as organo catalysts, [8] coupling partners [9] and directing groups in Pd-catalyzed cross-coupling reactions. [10] Therefore, organophosphorus compounds attract increasing attention from academic and industrial researchers.…”

Ionic iron(III) complexes bearing a dialkylbenzimidazolium cation: Efficient catalysts for magnesium‐mediated cross‐couplings of aryl phosphates with alkyl bromides

“…In fact, phosphates represent an attractive alternative electrophile not only because of their vast abundance in living organisms, but also because phosphates have simple and inexpensive preparation methods. Furthermore, phosphates are even more environmentally benign and stable than phenolic derivatives . Begtrup and co‐workers first reported the alkylation of alkenyl phosphates by n BuMgCl in the presence of Fe(acac) 3 (acac = acetylacetonato); however, only two moderate‐yielding examples were described .…”