Vinylene carbonate phenols

These pyrones undergo Diels-Alder reactions with electron-deficient alkenes with loss of COj and formation of an aromatic ring. Thus reaction with 1,1-dimethoxyethylene (11, 279-281) provides a regiospecific route to methyl salicylates (e.g., 3), which are convertible in several steps into catechol derivatives (4) or by decarbomethoxylation into phenol ethers (5). Similar reactions with vinylene carbonate or 1, 1,2-trimethoxyethylene provide regiospecific routes to phenols, differentially protected derivatives of catechol, resorcinol, or pyrogallol (equation II). 

Addition of vinylene carbonate to 1,2,3,4-tetraphenylcyclopentadieneone gives 80 % of the Diels Alder addition product which upon thermolysis or photolysis yields 95 % of 2,3,4,5-tetraphenylphenol105). Other substituted alkyl-aryl-phenols are synthesized by a similar route, using 2-alkyl-3,4,5-triphenylcyclopentadienones110). 

The cationic rhodium(I)/BINAP complex catalyzed decarboxylative [2 - - 2 - - 2] cycloaddition of diynes with commercially available vinylene carbonate to give bicyclic phenols in good yields (Scheme 4.47) [50]. In this reaction, vinylene... 

Other recent applications of ToF-SIMS without XPS include the examination of PS [6, 17-19], polyethylene (PE) [20], carbon fibre reinforced epoxy resins [21], polyalkyl methacrylates [22], alkylketene dimers [23], perfluorinated polymers [24], perflnorinated ethers [25], polyethylene glycol (PEG) oligomers [15, 25-29], rubber [30], ethylene-tetrafluoroethylene copolymer [30], Nylon-6 [31], PC [32,33], PDMS [34], polypyrrole coated PS [35], poly-p-phenylene vinylene [36], butyl rubber [37], poly(4-vinyl phenol)/poly(4-vinyl pyridine blends) [38], polypyrrole-silica gel composites [39], y-glycidoxypropyl trimethoxy silane [40], triblock copolymer poly(ethylene glycol)- 3 poly(phenylene ethylene)- 3 poly(ethylene glycol) [41], ethylene-terephthalate-hydroxybenzoate copolymer [42], PS-polyvinyl methyl ether, polycarbonate - PS blends [43] and PDMS-urethane [44],... 

Complementary HPLC-MS has also applied to structure elucidation in other polymers including polyethylene terephthalate [10], phenol oligomers [11], phosphoric acid containing polyarylene ethers [12], isocyanates [13], polyurethanes [14], polyamindoamine dendrimers [15], N-isopropyl acrylamide [16], oligo-(phenylene-vinylene) dimer [13], polyetherether ketone [17] and carbon blacks [18]. 

---