Reexamination of the Evidence for Solvent-Induced Intramolecular Electrophilic Catalysis by acis Vicinal Hydroxyl Group in Ribonucleoside Phosphorylation Reactions

Abstract

The vicinal hydroxyl group accelerates the second stage of the sequence leading to 2′‐ and 3′‐dialkyl nucleotide triesters 3 and 4 because it enables formation of the reactive 2′,3′‐cyclic phosphorochloridate intermediate 2 a/b (mixture of diastereoisomers); it is not because of electrophilic catalysis (hydrogen bonding) in acyclic phosphorodichloridates as recently proposed.

A New Neighbouring‐Group Reaction to Form Pyridopyrrolobenzoxazinediones

“…Similarly, the reaction of γ‐keto‐acid chlorides and o ‐aroylbenzoyl chlorides with hydroperoxides delivered heterocyclic peroxides 3d. Ribonucleoside phosphodichloridate, with a free cis ‐vicinal hydroxy group, shows a definite rate enhancement upon alcoholysis relative to the cis unsubstituted compounds 3e, 3f. Also, N ‐acyl functions have been shown to promote the conversion of nitriles into carboxamides under mild conditions by a neighbouring‐group effect,3g and 2‐carbamoylbenzoates readily release fragrance alcohols by neighbouring‐group‐assisted alkaline hydrolysis 3h.…”