Novel applications of the "Cesium Effect" in organic synthesis: Regioselective ring opening of epoxides with phenylselenol for the preparation of -hydroxy selenides and a mild and highly efficient synthesis of organosilanes

ORGN 148

Adam K. Nischwitz,, John Frey, John Jonathan C. Pendley, and Ralph Nicholas Salvatore. Department of Chemistry, University of Massachusetts-Boston, 100 Morrissey Blvd., Boston, MA 02125
-hydroxy selenides are crucial synthetic intermediates used in a wide variety of transformations. Numerous methods exist for the preparation of these compounds, however, such reactions often lack regioselectivity, result in poor product yields and employ cumbersome reagents. Thus, a more convenient route would be of great interest. We describe here an efficient method for the ring opening of epoxides via the phenylselenide anion. Various epoxides were transformed into their corresponding -hydroxy selenides using PhSeH and CsOH. The ring opening reaction was found to be highly regioselective. In turn, the incorporation of silicon into organic molecules is an equally attractive goal, since organosilanes are becoming increasingly popular due to their robust biological and pharmacological properties. However, construction of C-Si bond still remains a formidable challenge. Therefore, we have now embarked on a novel methodology for the alkylation of trialkylsilanes with alkyl halides using the aforementioned approach. Application of this methodology toward the synthesis of silyl amino acids and silicon-based peptidomimetics are being explored and these results will be reported in due course.


New Reactions and Methodology, Materials, Total Synthesis, Process R&D
8:00 PM-10:00 PM, Sunday, 28 August 2005 Washington DC Convention Center -- Hall A, Poster

8:00 PM-10:00 PM, Monday, 29 August 2005 Washington DC Convention Center -- Hall A, Sci-Mix

Division of Organic Chemistry

The 230th ACS National Meeting, in Washington, DC, Aug 28-Sept 1, 2005