Squalene Cyclization

Citation

Schaefer, Phillip Cuthbert (1969) Squalene Cyclization. Dissertation (Ph.D.), California Institute of Technology. doi:10.7907/GV74-NT60. https://resolver.caltech.edu/CaltechETD:etd-10032002-124237

Abstract

It has been observed that the proton, which is located at C-14 in squalene or C-13 in the "presterol cation," migrates less than 10% of the time (with a confidence level of 74%) to C-20 in lanosterol, and therefore 90% of the time (with a confidence level of 74%) to C-17 in lanosterol. If enzymatically controlled reactions are stereospecific, then at C-13/C17/C-20 in the "presterol cation," there are two sequential 1, 2-migrations during the backbone rearrangement to form lanosterol. A theoretical interpretation of this observation, which reflects on the stereochemistry of the C-18/C-19 double bond of squalene just prior to cyclization, is presented.

A theoretical discussion of the minimal requirements for binding squalene-2, 3-oxide to an enzyme in order to obtain complete stereochemical control over the product is presented.

Thesis Files