Reactivity of furans promoted by a tungsten pi base

ORGN 276

Kimberley C Bassett, kcb6j@virginia.edu1, Matthew Olsen, mo2c@virginia.edu1, William H. Myers2, Michal Sabat, ms5c@virginia.edu1, and W. Dean Harman1. (1) Department of Chemistry, University of Virginia, McCormick Rd, P.O. Box 400-319, Charlottesville, VA 22904, (2) Department of Chemistry, University of Richmond
When coordinated to the pi-basic transition metal fragment{TpW(NO)PMe3}, where Tp = hydridotris(pyrazolyl)borate, the reactivity of furans is altered. This tungsten complex binds furans in a dihapto fashion, dearomatizing the ligand. The unbound portion of the furan is activated at the beta position, mimicking the reactivity of a vinyl ether. We have been able to take advantage of this reactivity and have synthesized a number of dihydrofurans as well as pyranofurans in respectable yields. Binding furan in this fashion also gives us access the carbonyl ylide isomer of the furan, promoting [3+2] dipolar cycloaddition. Progress has been made towards the demetallation of these complexes.

 

Metal-Mediated Reactions and Syntheses
1:00 PM-5:00 PM, Monday, 29 August 2005 Washington DC Convention Center -- 202B, Oral

Division of Organic Chemistry

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