Rhodium Catalyzed C-H Bond Functionalization: Development of Methods and Applications in Organic Synthesis
Chapter 1. A sequence of research projects beginning with studies in diastereoselective C-H bond functionalization applied to the synthesis of (-)-incarvaillateine to the Rh(III) catalyzed arylation of imines, are described. Some theory and mechanistic considerations are discussed in relation to the genesis of these projects. Research directions are summarized and rationalized.
Chapter 2. The synthesis of (-)-incarvillateine utilizing a key C-H bond alkylation step is described as a means to highlight the synthetic utility of a newly reported olefinic C-H bond functionalization methodology. Elements of diastereoselectivity are also explored in the key step which allows for the concise, stereoselective synthesis of the natural product. Progress in the area of enantioselective C-H alkylations are also summarized as it applies to the synthesis of other natural products.
Chapter 3. A method for the enantioselective cyclization of N-allylimidazoles is developed. The reaction is thought to proceed via a novel, reactive N-heterocyclic carbene. High enantioselectivities are achieved, which is unusual in view of the elevated temperatures of the reaction.
Chapter 4. The first general method for the oxidative coupling of unactivated alkenes via C-H bond functionalization is reported using a methyl oxime directing group. A silver abstractor is important to obtain reactivity. Several functional groups are compatible with the reaction and no precautions to exclude air are required.
Chapter 5. A rare example of C-H activation and intermolecular coupling to N-protected-imines is achieved using a cationic Rh(III) catalyst. The reaction is directed by pyridines and related heterocycles and produces a variety of aryl-branched amines. The reaction accommodates several reactive functional groups and is mild enough to even couple with sensitive alkyl N-sulfonyl-imines.