Diastereoselective Synthesis of C60/Steroid Conjugates
详细信息 查看全文
- 作者：Alberto Ruiz ; Julieta Coro ; Luis Almagro ; Jos茅 A. Ruiz ; Dolores Molero ; Enrique E. Maroto ; Salvatore Filippone ; Mar铆a 脕ngeles Herranz ; Roberto Mart铆nez-脕lvarez ; Juan Carlos Sancho-Garc铆a ; Florent Di Meo ; Margarita Su谩rez ; Nazario Mart铆n
- 刊名：The Journal of Organic Chemistry
- 出版年：2013
- 出版时间：April 5, 2013
- 年：2013
- 卷：78
- 期：7
- 页码：2819-2826
- 全文大小：388K
- 年卷期：v.78,no.7(April 5, 2013)
- ISSN：1520-6904
文摘
The design and synthesis of fullerene鈥搒teroid hybrids by using Prato鈥檚 protocol has afforded new fullerene derivatives endowed with epiandrosterone, an important naturally occurring steroid hormone. Since the formation of the pyrrolidine ring resulting from the 1,3-dipolar cyloaddition reaction takes place with generation of a new stereogenic center on the C2 of the five-membered ring, the reaction proceeds with formation of a diastereomeric mixture [compounds 6 and 7 in 70:30 ratio, 8 and 9 in 26:74 ratio (HPLC)] in which the formation of the major diasteroisomers 6 and 9 is consistent with an electrophilic attack of [60]fullerene on the Re face of the azomethine ylide directed by the steroidic unit. The chiroptical properties of these conjugates reveal typical Cotton effects in CD spectra that have been used to assign the absolute configuration of the new fulleropyrrolidines. The electrochemical study of the new compounds reveals the presence of four quasi-reversible reduction waves which are cathodically shifted in comparison with the parent C60, thus ascertaining the proposed structures.