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This Thesis describes the development of telescoped rhodium(II)-catalysed transformations of α-diazo(diethoxyphosphoryl)acetates for the formation of α-methylene-γ-butyrolactones. An overview of synthetic approaches to α-methylene-γ-butyrolactones is given in Chapter 1, in addition to a discussion of published Rh(II)-catalysed C–H insertion reactions. Previous efforts in the Taylor group have established effective methods for the synthesis of α-methylene-γ-butyrolactones, although these require relatively complex functionality in the precursors. The research in this Thesis focuses on the development of a one-pot Rh(II)-catalysed C–H insertion/olefination sequence for the synthesis of α-methylene-γ-butyrolactones III from α-diazo(diethoxyphosphoryl)acetates I, which are readily accessible from simple alcohols. The key C–H insertion step enables the formation of a new C–C bond in α-phosphonolactone II, via reaction of the rhodium carbenoid with a C–H bond typically considered completely unreactive. The scope of the reaction is explored in detail, concluding with the synthesis of two natural products, cedarmycins A and B (IV and V) and a Staphylococcus Aureus inhibitor VI (Chapter 2). The scope of the reaction was extended to the use of conformationally restricted substrates,facilitating the synthesis of α-methylene-γ-butyrolactones with complete diastereoselectivity,demonstrated through the synthesis of the natural product α-cyclocostunolide VII (Chapter 3). Finally, the development of a related procedure is described (Chapter 4). The rhodium(II)-catalysed cyclopropanation of allylic α-diazo(diethoxyphosphoryl)acetates is discussed as an alternative approach to the α-methylene-γ-butyrolactone framework. This work has been applied to the first total synthesis of peperomin E VIII as well as savinin IX and gadain X (Chapter 4).

The anthraquinone process is the most important method in the manufacture of hydrogen peroxide. The hydrogenation of anthraquinone is the key reaction in this method. Because of the instability of the product in this reaction, and the lack of anthraquinone measuring method during the reaction, the mechanism study on this reaction was exclusively based on the hydrogen consumption and the stoichiometry relationship between hydrogen and anthraquinone. Hence we introduce IR in situ detection, which is a powerful technique that has the ability to directly study the mechanism by monitoring not only the anthraquinone consumption but also the product formation in the hydrogenation of anthraquinone. It is worth to notice that this is the first time that the unstable product anthrahydroquinone be detected by the researchers. By using in situ IR and hydrogen consumption measurement orthogonality, a great advantage had been shown not only in the study of the kinetic of the primary hydrogenation of anthraquinone, but also in studying the degradation of the primary product anthrahydroquinone when comparing to the conventional methods. In situ IR shows its potential to be a powerful technique in the mechanism study of reactions that involve intermediate detection. Different supports for palladium loading had be studied for the hydrogenation of anthraquinone. Among these supports, the dealuminated Y zeolite supported Pd catalyst shows a 38% improve in the activity to γ-alumina supported Pd catalyst, the latter is widely used as a commercial catalyst in the hydrogen peroxide manufacture. Besides this, water promotes both the primary hydrogenation rate and degradation rate in the hydrogenation of anthraquinone. Phenyl grafted MCM41 support suppresses the water effect in the degradation, showing a 42% less degradation rate and 15% more selectivity to active quinone when compared to commercial catalyst. The possible explanation is that its hydrophobic property hinder the contact between catalyst and primary product.

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