- Poly(thioester) by Organocatalytic Ring-Opening Polymerization
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Organocatalysts typically used for the ring-opening polymerization (ROP) of cyclic ester monomers are applied to a thiolactone, ε-thiocaprolactone (tCL). In the absence of an H-bond donor, a nucleophilic polymerization mechanism is proposed. Despite the decreased ability of thioesters and thiols (versus esters and alcohols) to H-bond, H-bonding organocatalysts - a thiourea in combination with an H-bond accepting base - are also effective for the ROP of tCL. The increased nucleophilicity of thiols (versus alcohols) is implicated in the increased Mw/Mn of the poly(thiocaprolactone) versus poly(caprolactone), but deleterious transesterification is suppressed in the presence of a thiourea. The thioester monomer, tCL, is shown to be thermodynamically similar to ε-caprolactam but kinetically similar to ε-caprolactone. (Chemical Equation Presented).
- Bannin, Timothy J.,Kiesewetter, Matthew K.
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- Synthesis of thiolactones using benzyltriethylammonium tetrathiomolybdate as sulfur transfer reagent
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An interesting sulfur transfer reaction mediated by benzyltiethylammonium tetrathiomolybdate [(PhCH2NEt3)2MoS4] converts ω-halo acid chlorides to the corresponding thiolactones in moderate to good yields in one
- Bhar, Debjani,Chandrasekaran
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p. 11835 - 11842
(2007/10/03)
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