I. Synthesis and Utilization of Diazocompounds for Applications in Solution-Phase and Gas-Phase Chemistry. II. Progress Toward the Communesin Alkaloids

Citation

May, Jeremy Allen (2006) I. Synthesis and Utilization of Diazocompounds for Applications in Solution-Phase and Gas-Phase Chemistry. II. Progress Toward the Communesin Alkaloids. Dissertation (Ph.D.), California Institute of Technology. doi:10.7907/dkek-2c97. https://resolver.caltech.edu/CaltechETD:etd-03062006-135435

Abstract

Advances in the synthesis and use of diazo compounds are first discussed. The development of non-carbonyl stabilized diazo equivalents has allowed for carbene reactivity to be localized at carbons not adjacent to carbonyls. Consequently, a new tandem sequence, the Bamford-Stevens/Claisen reaction, has been developed that incorporates selective Z-enol ether formation with a thermal- or Lewis acid-promoted Claisen reaction. Bamford-Stevens/Claisen/Carbonyl Ene and Bamford-Stevens/Claisen/Cope reactions have also been realized.

Also discussed is the application of diazocompounds to gas-phase chemistry with peptides. Crown ethers are used for binding to primary amines, and a diazomalonate is incorporated for generation of a highly reactive carbene within a non-covalent complex. Intermolecular insertion reactions can then occur in these complexes. Electrospray ionization mass spectrometry and density functional theory (DFT) are utilized to evaluate the reactions for small molecules and peptides, as well as metal-promoted Wolff Rearrangement in the gas phase.

Finally, the biosynthesis of the calycanthaceous alkaloids is examined. The development of an approach to the alkaloid communesin B is presented. The approach is based on considerations of a possible biosynthetic sequence involving an oxidative coupling of tryptamine with a derivative of the ergot alkaloid aurantioclavine. Structure revision is also suggested for the recently isolated microfilament disrupting alkaloid nomofungin. Crystallographic evidence is presented for products from the proposed inverse-demand Diels-Alder reaction.

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