| ?-Methylene-?-lactam units are important scaffolds found in some biologically active molecules and natural products. Compared with their isosteric ?-methylene-?-lactones, ?-methylene-?-lactams display much lower toxic side effects while maintaining similar bioactivities in antibacterial, antiinflammatory, antianaphylactic, and anticancer properties. They are also versatile building blocks in organic synthesis. Thus, the development of appropriate synthetic strategies for obtaining these frameworks has received much attention over the past several decades. On the other hand, because organotin compounds usually display good stability toward heat, hydrolysis, and oxidation, tolerance to functional groups, and high selectivity in organic reactions, they are extensively used in organic synthesis. However, organotin reagents are of disadvantages because they are toxic and their atoms are not economic in reaction. Besides, some studies found that tin powder can form organotin reagent in situ to react with substrates directly in reaction. This is of great advantages because it avoids the complex process for the preparation of organotin reagents and the use of the toxic organotin reagents, but also greatly improve the utilization rate of the atom. Hence, it is of great significance to explore the organic reaction promoted by tin powder. A new method for the synthesis of ?- methylene-?- butyl lactam compounds was explored in this thesis.Thesis is consisted of three chapters:Chapter one: Research progress in the application of organotin reagents in organic synthesis.The application of organotin reagents in organic synthesis is introduced and then reactions promoted by tin powder are mainly reviewed in this chapter.Chapter two: Tin powder-promoted one-pot construction of ?-Methylene-?-lactams and spirolactams from aldehydes or ketones, acylhydrazines, and 2-(bromomethyl)acrylate.A novel method for the construction of ?-methylene-?-lactams is developed from multicomponent one-pot reactions of aldehydes or ketones, hydrazides, and ethyl 2-(bromomethyl)acrylate promoted by tin powder, and 41 ?-methylene-?-lactams are synthesized in this chapter. In particular, ?-methylene-?-spirolactams can also be obtained from cyclic ketones. Our reaction has following advantages: without using any catalysts, milder conditions, easy operation and high yield, which provides a new method for the synthesis of ?-methylene-?-lactams.Chapter three: Tin-mediated one-pot synthesis of allyl ketopiperazine compounds from ethyl glyoxylate, o-phenylenediamine and allyl bromide.Ketopiperazine units are often found in many pharmacetical molecules with anticancer, antibacterial and anti-parkinson. One-pot reaction for the preparation of ketopiperazine from ethyl glyoxylate, o-phenylenediamine and allyl bromide promoted by tin powder is preliminarily explored in this thesis. |
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