Cyclic Ketene Acetals: Synthesis, Reaction and Polymerization
Peter Zhu, Ph.D.
Director of Polymer Science
Cyclic ketene acetals (CKAs) are a subgroup of the ketene acetal family and have similarities in structure with ketenes, acetals and vinyl ethers. They are very reactive and special techniques and conditions are needed for their synthesis and isolation. Specifically, an O,O-cyclic ketene acetal is analogous to a vinyl ether twice reinforced. Similarly, an O,N-cyclic ketene acetal may be thought of as both a vinyl ether and an enamine simultaneously, where both the vinyl ether nature and the enamine nature reinforce the nucleophilicity of the reactive carbon. This is illustrated below for an O,N-CKA.
Thus, CKAs are exceptionally nucleophilic and the exocyclic carbon is readily protonated. In the presence of trace amounts of cationic species, such as protonic or Lewis acids, CKAs undergo chemical reactions and ring-opening polymerization with interesting behavior. For example, the 1,2-addition polymer A can be a precursor to polyketene, B.
An example of the exceptionally high nucleophilicity of the exocyclic carbon is illustrated by the reaction of O,N-CKAs with phenyl isocyanate. The adduct 1 has one electron withdrawing amide function but it still rapidly adds to a second phenyl isocyanate molecule to give 2.
In this lecture, the synthesis, chemical reactions and cationic polymerization of CKAs will be discussed in detail. The author will also discuss in some detail the potential CKA chemistry applications.
Peter Zhu is currently Director of Polymer Science, Emerging Technologies, CooperVision. He was former JNJ Research Fellow /Principal Scientist, 3M Sr Research Scientist/Sr Research Scientist II, and Irvine Valley College adjunct professor.
Peter’s industry research experience includes drug delivery, particularly transdermal, functional polymers, organic synthesis and process, natural product chemistry, fluorescent sensor chemistry (of K+, Na+, glucose, O2, CO2 and pH), DNA chip, conjugation chemistry, nanochemistry and dendrimer application, drug abuse deterrence, hydrogel polymer and formulation. His favorite interests include innovation methodologies and “molecular engineering”. Peter is author of numerous patents, papers, presentations and books. He also organized several ACS symposia. Peter is a member of ACS, ASM, APIC, AAPS, BCLA etc. Peter’s name was included in Marquis Who'sWho in America etc.
Peter obtained his BS in Pharmacy 1981 and MS in Medicinal Chemistry 1987 from Jiangxi College of Chinese Medicine, China and his Ph.D. in Polymer/Organic Chemistry 1993 from Mississippi State University. He did his postdoctoral research in synthetic organic chemistry at UC Santa Barbara.
Tuesday, August 19
Michael's Restaurant at Shoreline Park
2960 N Shoreline Blvd
Mountain View, CA 94043
6 PM social hour
7 PM dinner
8 PM lecture
$30 with advance registration
Half price for students, retired, and unemployed. (late fee still applies, if applicable)
Free if you attend just the lecture at 8PM. (but please let us know for headcount)
$40 after registration deadline, if possible -- please contact us to inquire.
we accept cash or checks, but are unable to accept payment by credit card at this time. You may pay at the door.
Please register on the web page http://www.ggpf.org/ or contact:
Deadline for registration:
5 PM, Monday August 18
broiled salmon with a lemon buerre blanc
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