| Summary: | 1. Abstract The work reported in this thesis is divided into two parts. In the first part, the chemistry of N-silyloxy enamine is discussed. The introductory section contains a brief overview of enamines, N,N-bis(silyloxy)enamines and N-silyloxy enamines, including their preparation, reactivity as well as comparison of their nucleophilicity with enolates and silyl enol ethers. Enamines in aldol reactions and synthetic challenges of asymmetric cross-aldol reactions are briefly discussed. The results and discussion section describes the synthesis of N-silyloxy enamines derived from aldehydes and use of N-(trimethylsilyloxy)enamines as new aldehyde enolate synthons for general, efficient and diastereoselective aldol-type reaction with dimethyl acetals and ketals. Also the syn-diastereoselectivity in β-methoxy nitrone products and their conversion to respective β-methoxy aldehydes is mentioned. Furthermore, synthesis of N-methyl-N-(trimethylsilyloxy)enamines from ketones is reported. In the second part, synthesis of new symmetric and non-symmetric helquats is reported. In the introductory section a brief overview of N-heteroaromatic cations including their natural occurrence and synthetic aspects as well as their applications in organocatalysis, molecular biology is discussed. Helicenes, viologens,...
|
|---|
