Hui, Chun-Ngai2022-02-022022-02-022021http://hdl.handle.net/2003/4070810.17877/DE290R-22566Carbocycles are omnipresence in chemical pharmaceuticals, biologically active natural products and organic functional materials. Construction of structurally intriguing, highly functionalized small carbocycles with congested stereocenters remain to be an intricate task in organic chemistry. Consistent endeavor such as innovation of chemical methodology and development of synthetic tactics has been made to improve the synthetic efficiency to these complex structures. In particular, the synthesis of carbocycle through ring contraction, which complies with the concept of synthetic efficiency in modern organic chemistry, has been widely applied in organic synthesis of complex architectures. In this thesis, the unprecedented, stereospecific and contractive synthesis of multi-substituted cyclobutanes from corresponding pyrrolidines is discussed. The reaction mechanism is investigated and the reaction was applied to the synthesis of cytotoxic natural product piperarborenine B.enCyclobutanesIodonitrenes' contractive synthesisNatural product synthesis570540doctoral thesisNaturstoffchemieCyclobutanderivate