Font Size: a A A

The Chemical Transformation Of Per-(Or Poly) Fluorophenyl Aromatic Aldimines And Synthesis Of N-per (Or Poly) Fluorophenyl Pyrroles And N-fluoroalkanesulfonyl Pyrroles

Posted on:2005-01-20Degree:MasterType:Thesis
Country:ChinaCandidate:X Y LiuFull Text:PDF
GTID:2121360122986874Subject:Organic Chemistry
Abstract/Summary:PDF Full Text Request
In this thesis, two series of derivatives of per- (or poly)fluoroanilines (ArFNH2) including N-sulfinyl per- (or poly)fluoroanilines and per- (or poly)fluorophenyl aromatic aldimines were prepared. From these derivatives, a series of novel fluorine-containing compounds such as heterocycles and amines, were synthesized. The whole thesis consists of three parts. Part I. In order to overcome the problem of slow reaction rate of the Baylis-Hillman reaction, we employed per- (or poly)fluorophenyl aromatic aldimines as the electrophiles. We examined the aza-Baylis-Hillman reaction of per- (or poly)fluorophenyl aromatic aldimines with various olefins, and found that the reactions of per- (or poly)fluorophenyl aromatic aldimines with active olefins were greatly accelerated in some cases. The Lewis bases, solvents and substrates can significantly affect the aza-Baylis-Hillman reaction rate and even products. The aza-Baylis-Hillman reactions of methyl acrylate and acrylonitrile with per- (or poly)fluorophenyl aromatic aldimines can be accomplished within short time to give the normal aza-Baylis-Hillman adducts in moderate to good yields under the appropriate conditions. A facile efficient methodology for the preparation of fluorine-containingβ-amino-α,β-unsaturated carbonyl compounds was developed. In the aza-Baylis-Hillman reaction of methyl vinyl ketone with per- (or poly)fluorophenyl aromatic aldimines , we found that the reaction can be greatly accelerated to give the normal aza-Baylis-Hillman adducts and the tandem Michael / aza-Baylis-Hillman adducts in moderate to excellent yields in the presence of catalytic amount of PPh3. However, the reaction of methyl vinyl ketone with per- (or poly)fluorophenyl aromatic aldimines produced the tandem Michael / aza-Baylis-Hillman adducts with the single anti conformation by using DABCO as a catalyst. A plausible mechanism of the tandem Michael / aza-Baylis-Hillman reaction was proposed based on the experimental results and the high stereoselectivity of this reaction was also explained. In addition, the one-pot Baylis-Hillman reactions of aryladehydes and per- (or poly)fluoroanilines with methyl vinyl ketone in the presence of TiCl4, PPh3, and Et3N was also investigated. We found that the best reaction condition for this one-pot Baylis-Hillman is PPh3 (0.1 equiv.) as the Lewis base and TiCl4 (0.8 equiv.) as the Lewis acid in the presence of Et3N (12 equiv.). Under the optimized reaction conditions, the one-pot Baylis-Hillman adducts can be obtained in moderate to good yields. A plausible mechanism of the one-pot Baylis-Hillman reaction was proposed based on the obtained results.Part II.We have examined the zinc–mediated radical reaction of per- (or poly)fluorophenyl aromatic aldimines in aqueous media. We found that per- (or poly)fluorophenyl aromatic aldimines can act as radical acceptors in aqueous media. These are the first examples of the reaction of per- (or poly)fluorophenyl aromatic imines with carbon radicals. The alkylated or coupled products could be isolated depending on the media, alkyl group, and substituent groups on R1 and R2 of the substrates. This reaction provides a convenient method for preparing a wide range of fluorine-containing amine derivatives. A tentative mechanism for the radical reaction was proposed based on the obtained results.Part III.We have efficiently synthesized N-per- (or poly) fluorophenyl pyrroles and N-fluoroalkanesulfonyl pyrroles. Firstly, we examined that (4+2(-cycloaddition of N-sulfinyl per- (or poly)fluoroanilines with 1,3-dienes in a sealed tube and the six-membered 2-(fluorophenyl)-3,6-dihydro-1,2- thiazine-1-oxides were obtained in good yield. Under basic reaction conditions, the six-membered 2-(fluorophenyl)-3,6-dihydro-1,2-thiazine-1-oxides readily transformed the corresponding N-fluorophenyl pyrroles in moderate to excellent yields. While Hetero-Diels-Alder reaction of N-sulfinylfluoroalkanesulfonyl amine with 1,3-diene afforded the corresponding cycloadduct 3,6-dihydro-1,2-thiazine-1-...
Keywords/Search Tags:active olefin, per- (or poly)fluorophenyl aromatic aldimine, Baylis-Hillman reaction, radical reaction, pyrrole, mechanism.
PDF Full Text Request
Related items