Date of Graduation

2001

Document Type

Thesis

Degree Type

MS

Committee Chair

Kay M. Brummond

Abstract

A novel immunosuppressant, FR901483 (1) was discovered by a Fujisawa company, which was isolated from the fermentation broth of a fungal strain. It exerts a potent immunosuppressive activity in vitro and significantly prolongs graft survival time in the rat skin allograft model. Our group has postulated a novel synthetic approach to the target compound (1) that can be used for the preparation of a structurally diverse set of compounds. And our group has successfully synthesized the aminoaldehyde 42 that possesses the core structure of FR901483 using the tandem cationic aza-Cope rearrangement-Mannich cyclization strategy. In order to apply this strategy to the real system, a much more functionalized azaCope-Mannich cyclization precursor is required, we reasoned that this precursor could be derived from aldol reaction of the aldehyde of L-tyrosine and the monoprotected 1,4- cyclohexanedione. Aldol reaction of the α-amino aldehyde 110 with keto ketal 37b and LDA in THF at –78 °C for 2.5 hour afforded 40% of one major diastereomer 111 and 43% of other three diastereomers. To our delight, the major diastereomer 111 has the desired stereochemistry of FR901483 by X-ray crystallography. Further reactions were made to try to complete the total synthesis of FR901483.

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