E-Locus - Institutional Repository of the University of Crete

Home Search

Results - Details

Search command : Author="Βασιλικογιαννάκης" And Author="Γεώργιος"

Current Record: 72 of 75

[Add to Basket]

Identifier

000324989

Title

Ολική σύνθεση των φυσικών προϊόντων Zerumin B, chinensines A-E και Premnalane στη βάση βιομιμητικών φωτοχημικών μετασχηματισμών του μοριακού οξυγόνου

Alternative Title

Total syntheses of the natural products zerumin b, chinensines a-e and premnalame in the context of biomimetic photochemical transformations mediated by molecular oxygen

Author

Μαργαρός, Ιωάννης Αντωνίου

Thesis advisor

Βασιλικογιαννάκης, Γεώργιος

Abstract

In this dissertation the successful syntheses of natural products that exhibit interesting biological activities are described. In particular, the first total synthesis of the antitumor diterpenoids Chinensine Β (3) and Chinensines A, C, D and Ε (2, 4-6) is disclosed herein. En route to the Chinensines, Coronarin E (1), as well as natural products 65, 79 and Villosin (92) were synthesized. Synthesis of the aforementioned natural products facilitated elucidation of their absolute stereochemistry. The regioselective synthesis of antitumor diterpenoids (+)-Zerumin B (7) and (+)-12-epi-Zerumin B (8)¹⁴¹ was also achieved. The synthesis of (+)-Premnalane A (9b) was also accomplished, allowing elucidation of its absolute stereochemistry. Synthesis of (+)–Premnalane A, also led us to the disclosure of a new efficient synthetic methodology for constructing [5,5] and [5,6] γ-spiroperoxy γ-lactones. Biomimetic strategies were incorporated into our synthetic plans as a result of a continuing effort to improve our synthetic designs. These biomimetic scenarios led to short and efficient synthetic routes for the construction of all these compounds. The use of singlet oxygen (¹Ο₂) harmonizes ideally with biomimetic synthetic strategies. Reactions of suitably substituted furans with singlet oxygen lie at the heart of many of these scenarios. Application of such biomimetic designs and strategies combined with the utilization of singlet oxygen’s many and versatile reaction modes, allowed for dramatic increases in molecular complexicity within short sequences and for impressive chemo- and regioselectivities. The one pot synthesis of Premnalane A, using a domino reaction sequence to convert a simple furan motif into an architecturally complex [5,6] γ-spiroperoxy γ-lactones, provides excellent example verifying this assertion. Furthermore and in general, the use of singlet oxygen as an oxidizing agent is in accordance with the demand for more environmentally benign chemical processes.

Language

Greek

Subject

Chinensine A

Chinensine B

Chinensine C

Chinensine D

Chinensine E

Coronarin E

Premnalene A

Villosin

Zerumin B