Iodoarene-catalyzed cyclizations of N-propargylamides and β-amidoketones: synthesis of 2-oxazolines

Two complementary iodoarene-catalyzed methods for the preparation of 2-oxazolines are presented. The first involves the cyclization of N-propargylamides and the second involves the cyclization of β-amidoketones. These are proposed to proceed through different mechanisms and have different substrate scopes

Development of Enantioselective and Catalytic Cyclisation Reactions Using Hypervalent Iodine Compounds

In this thesis, iodoarene and chiral iodoarene reagents have been developed and used catalytically in the enantioselective cyclisation reaction of unsaturated esters, amides and β-amidoketones. The results in this thesis are divided into three parts. In the first part, the development of the catalytic enantioselective cyclisation of 4-methoxy but-3-enyl benzoate to the 3-hydroxytetrahydrofuran ester using enantiomerically pure chiral hypervalent iodine reagents generated in situ is described. A good enantioselectivity of 77% ee was obtained with moderate yield. In the second part, the development of catalytic conditions for the cyclisation of N-alkenylarylamides induced by iodoarenes leading to the formation of different ring sizes is demonstrated. In addition, the catalytic enantioselective cyclisation of N-alkenylarylamides employing chiral iodoarenes giving dihydrooxazines in good yields and moderate enantioselectivities of up to 64% is achieved. In the third part, the catalytic cyclisation of both propargyl amides and β-amidoketones using 2-iodoanisole to afford 2-oxazolines in good yields is described. Moreover, the catalytic enantioselective cyclisation of β-amidoketones using several chiral iodoarenes is detailed but, unfortunately almost no enantioselectivities was observed

Iodoarene-Catalyzed Cyclizations of Unsaturated Amides

The cyclization of N-alkenylamides catalyzed by iodoarenes under oxidative conditions is presented. Five-, six-, and seven-membered rings with a range of substitutions can be prepared by this route. Preliminary data from the use of chiral iodoarenes as precatalysts show that enantiocontrol is feasible