ABSTRACT
The development and application of high-load, recyclable magnetic Co/C hybrid ROMP-derived benzenesulfonyl chloride and analogues is reported. The regeneration and utility of these reagents in the methylation/alkylation of various carboxylic acids is demonstrated via efficient retrieval of the magnetic reagent with a neodymium magnet. Additional reactions employing the analogue sulfonic acid and in situ generated magnetic benzenesulfonyl azide are also reported.
Subject(s)
Carbon/chemistry , Cobalt/chemistry , Magnetite Nanoparticles/chemistry , Sulfones/chemical synthesis , Alkylation , Carboxylic Acids/chemistry , Indicators and Reagents , Particle Size , Surface PropertiesABSTRACT
The syntheses of silica-supported oligomeric benzyl phosphates (Si-OBP(n)) and triazole phosphates (Si-OTP(n)) using ring-opening metathesis polymerization (ROMP) for use as efficient alkylating reagents is reported. Ease of synthesis and grafting onto the surface of norbornenyl-tagged (Nb-tagged) silica particles has been demonstrated for benzyl phosphate and triazole phosphate monomers. It is shown that these silica polymer hybrid reagents, Si-OBP(n) and Si-OTP(n), can be used to carry out alkylation reactions with an array of different nucleophiles to afford the corresponding benzylated and (triazolyl)methylated products in good yield and high purity.
Subject(s)
Benzyl Compounds/chemistry , Phosphates/chemistry , Silicon Dioxide/chemistry , Triazoles/chemistry , Alkylation , Molecular Conformation , Particle Size , Phosphates/chemical synthesis , Surface PropertiesABSTRACT
A new high-load, oligomeric monoamine hydrochloride (OMAm*HCl) derived from ring-opening metathesis polymerization (ROMP) of norbornene methylamine is reported. This oligomeric amine has been shown to be an effective scavenger of acid chlorides, sulfonyl chlorides and isocyanates. The reagent can be synthesized in a straightforward protocol from the Diels-Alder reaction of dicyclopentadiene (DCPD) 1 with allylamine (neat), formation of the corresponding ammonium salt and subsequent ROM polymerization to afford the desired oligomeric ammonium salts.
ABSTRACT
A strategy relying on the utilization of stereoselective additions to allyldiphenylphosphonate esters and subsequent ring-closing metathesis (RCM) to access P-chiral P-heterocyclic building blocks for the synthesis of phosphono sugars is described. These building blocks possess several attractive components, including the following: (i) P(2) and C(6) stereogenic centers for directing stereoselective transformations; (ii) an activated C(3) methylene group that promotes base-mediated olefin transposition to generate vinyl phosphonates available for further stereoselective reactions; and (iii) a P(2)-stereogenic center containing an exchangeable phosphonate ester armed to attenuate the "stereochemical environment" at phosphorus. Taken collectively, these attributes contribute to a concise method for the stereoselective synthesis of an array of P-sugars.
