We report the experimental determination of the intramolecular enol-enol tautomerization rate of an unsymmetric β-diketone, benzoylacetone, with femtosecond transient absorption in the ultraviolet. Initially, there is an equilibrium of two possible enolic structures in solution, which is disturbed upon UV excitation by exciting a disproportionate fraction of one enolic form. Comparison to symme...

Intramolecular C±H insertion by Rh-mediated carbenoids has attracted considerable interest in recent years. In addition to its synthetic applications, there have been extensive investigations into the mechanism of this reaction. We have recently studied the electronic e€ects of this reaction through the measurement of the relative reactivities of Rh-mediated carbenoid insertion into a series of...

1. Applicability of the previously postulated active transport system for conveying glucose into the human red cell was tested in connection with a number of related substances, comprising 6-carbon aldoses and ketoses, 5-carbon aldoses, and 5- or 6-carbon polyhydric alcohols. 2. The alcohols did not perceptibly penetrate the cells; all the sugars penetrated, the rates differing, but all of the ...

The asymmetric synthesis of chiral polycyclic ethers by an intramolecular [2+2] photocycloaddition is described.