Dr. William Bailey | University of Connecticut
Event Date:
April 25, 2016 – 4:00 PM to April 26, 2016 – 3:59 PM
Location:
Burson 115
Event Date:
April 25, 2016 – 4:00 PM to April 26, 2016 – 3:59 PM
Location:
Burson 115
|
Department of Chemistry
|
Dr. William Bailey
University of Connecticut
Department of Chemistry
Will be presenting
“Cyclohexanes by 6-exo Carbolithiation: Competition between Cyclization and Proton Transfer”
Abstract:
The 6-exo cyclization of a 6-heptenyllithium bearing a moderately anion-stabilizing group, such as phenyl or TMS, at the terminal olefinic carbon is a facile, high yield process. Cyclization of the parent 6-heptenyllithium to (cyclohexylmethyl) lithium is a much slower process that is compromised by [1,5]-proton transfer to give an allyllithium: under optimal conditions, the yield of (cyclohexylmethyl)lithium approaches 80 %. The 6-exo cyclization of methyl-substituted 6-heptenyllithiums proceeds with modest to good stereoselectivity via a transition state that resembles a cyclohexane chair.
Biography:
Development of new synthetic methodology using main-group organometallic chemistry. Investigation of the synthetic utility of unsaturated organolithiums and related Group 1 organo¬metallics. These reactive intermediates, prepared in virtually quantitative yield by low-temperature lithium-iodine exchange between t-butyllithium and an organoiodide, undergo regiospecific and highly stereoselective cyclization upon warming. The high degree of stereocontrol in these anionic cyclizations has led to development of one step, stereoselective syntheses of simple natural products and tandem-cyclization strategies for the preparation of bi- and polycyclic structures.
Monday, April 25, 2016 @ 4:00pm
Room 115 Burson
Refreshments served @ 3:45