Study On The Synthesis Of Several Heterocyclic And Carbocyclic Derivatives

In this thesis, novel synthetic methods for the preparation of benzothi(x)azoles,2H-pyran-2-ones andfunctionalized cyclopentene/cyclohexene derivatives have been developed. It mainly includes the followingthree chapters:In the first chapter, an efficient synthesis of2-benzoxazyl ketones and2-benzothiazyl ketones throughFeCl3·6H2O catalyzed tandem reactions of alkynyl bromides with2-amino(thio)phenols in ionic liquid hasbeen developed. Through these reactions, a series of benzothi(x)azoles were synthesized with good yields.Compared with the literature method, these procedures showed such advantages as simple procedure, mildreaction conditions and good yields.In the second chapter, a novel synthesis of diversely substituted2H-pyran-2-ones via the tandemreaction of allenic alcohols in water under the promotion of MWI was developed. Compared with organicsolvents, the reactions carried out in water is not only environmentally sustainable, but alsochemoselectively advantageous.In the third chapter, efficient synthesis of functionalized cyclopentenes and cyclohexenes throughtertiary phosphine catalyzed [3+2] and [4+2] annulations of1,2-allenic ketones with activated alkenes havebeen developed. Specific studies are as follows:1. Tertiary phosphine catalyzed [3+2] annulations of1,2-allenic ketones with benzylidenemalononitrile were studied. Through these reactions, a series of cyclopentenyl ketones derivatives weresynthesized with good yields.2. Tertiary phosphine catalyzed [4+2] annulations of2-substituted allenic ketones with benzylidenemalononitrile or2-cyano-3-phenyl-acrylic acid ethyl ester were studied. Through these reactions, a series ofcyclohexenyl ketones derivatives were synthesized.In summary, several novel synthetic methods for the preparation of benzothi(x)azoles,2H-pyran-2-ones and cyclopentenyl/cyclohexenyl ketones have been developed in this thesis. Withadvantages such as environmentally benign nature, mild reaction conditions and high efficiency, thesemethods are expected to find broad applications in synthetic organic chemistry and related areas.