[化学]The Mechanism of Lithium-Halogen Exchange.pdfVIP

The Mechanism of Lithium-Halogen Exchange K eq R1 X Li R2 Li R1 R2 X MacMillan Group Meeting February 22, 2007 Sandra Lee Key Articles: Bailey, W. F.; Patricia, J. J. J. Organomet. Chem. 1988, 352, 1–46. Seyferth, D. Organometallics 2006, 25, 2–24. Schlosser, M. Organoalkali Chemistry. In Organometallics in Sy nthesis, A Manual: Schlosser, M., Ed; Wiley Sons LTD: West Sussex, U. K. 2002, pp 5–352. Beginnings of Main-Group Organometallic Chemistry ■ Me Zn: The first main group organometallic compound was discovered 2 by Frankland in 1849 When, on Jul y 28, 1848, Edwar d Fr ankl and, then a 23-year-ol d facul ty member of Queenwood Col l ege i n Hampshi r e, Engl and, fi l l ed a thi ck-wal l ed gl ass tube wi th fi nel y gr anul ated zi nc and ethyl i odi de and then seal ed i t, he di d not r eal i ze that he had set up the r eacti on that woul d pr oduce the fi rst mai n-gr oup or ganometal l i c compounds, ethyl zi nc i odi de and di ethyl zi nc... Hi s goal was the pr epar ati on and i sol ati on of the ethyl “r adi cal ”. ■ Lithium organic compounds: physical and chemical properties The small size of Li+ compared to other the other alkali-metal cations results in a much greater polarizing power (i.e. charge density) covalent ionic Li+ = 1.66