Synthetic Approaches Towards Six-membered Hetero- and Carbocyclic Fluorinated Organophosphonates

  • A series of CF2-containing alkynylphosphonates I-V have been employed in N,C-, O,C- and C,C-cyclizations with various 1,4-bipolar substrates to give polyfunctionalized hetero- and carbocyclic products, respectively. A variety of starting materials, such as 2-amino-3-formylchromones, 2-aminobenzaldehyde imines, 2-aminoacetophenones, 2-aminobenzophenones and 2-aminobenzonitriles were used as 1,4-bipolar substrates. As a result, we have synthesized novel polyfunctionalized pyridine/quinolines bearing difluoromethylated and phosphonate groups at 2- and 3-positions, respectively. Depending on the electrophilic center on these particular 1,4-bipolar substrates, the quinoline ring was substituted by H, CH3, CF3, Ph and NH2 groups at the 4-position. We have also demonstrated that symmetrical P(O)(OEt2)-acetylene VI reacting with 2-aminobenzonitriles led to 4-aminoquinolin-2,3-ylbisphosphonates. The reaction of VI with 2-aminobenzonitrile through unusual N,N-cyclization proceeded towards a 2,3-diphosphonate 1,4-benzodiazepine derivative in fairly good yield. The second section contains a study on O,C-cyclization of perfluoroalkyl alkynylphosphonates (CF3 I and C2F5 II) with 2-hydroxybenzaldehydes to afford chromenes. We showed that trialkyl amines (phosphines) as mediators provided the target 4H-chromenes; whereas PPh3 changed the regioselectivity resulting in 2H-chromenes carrying only CF3 group at the 2-position. We have also reported the isomerization process of 4H-chromenes into 2H-chromenes with almost quantitative yields. The third section concerns reactions of 1,4-bipolar substrates containing an acidic CH2 group (in-situ generated carbanion) with XF2C-acetylenes I-V via C,C-cyclization. The synthesis of polysubstituted benzene and naphthalene derivatives has thus been accomplished. Additionally, we have presented that the reaction of P(O)(OEt2)-acetylene VI with (2-cyanomethyl)benzonitrile underwent unexpected migration of one of the phosphonate groups. Finally, factors, such as substituents on the aryl ring as well as fluorinated groups in I-V, basic mediator and reaction media (solvents) that influence on the regioselectivity, specificity and efficiency of these hetero- and carbocyclization reactions have been disclosed.

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Publishing Institution:IRC-Library, Information Resource Center der Jacobs University Bremen
Granting Institution:Jacobs Univ.
Author:Blazej Duda
Referee:Gerd-Volker Röschenthaler, Detlef Gabel, Peer Kirsch, Sergey N. Tverdomed
Advisor:Gerd-Volker Röschenthaler
Persistent Identifier (URN):urn:nbn:de:101:1-201305294991
Document Type:PhD Thesis
Date of Successful Oral Defense:2012/08/31
Date of First Publication:2012/11/19
PhD Degree:Chemistry
School:SES School of Engineering and Science
Library of Congress Classification:Q Science / QD Chemistry / QD241-441 Organic chemistry
Call No:Thesis 2012/37

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