Sample A

Conversion Of Optically Active Acid-Esters To Ester-Acid Chlorides Without Loss Of Optical Activity
Sean Purdy (Senior, Chemistry), Mason Marsh (Senior, Chemistry)
Stephen Flowers (Junior, Biology), Brenda Benfield (Junior, Biology)
Advisor: Dr. George B. Trimitsis, Chemistry

It has been reported in the literature that attempts to convert optically active acid-esters to their corresponding ester-acid chlorides by standard procedures is often accompanied by loss of optical activity. The purpose of the present investigation was to develop a suitable experimental procedure for the conversion of methyl (R)-3-methyl glutarate (1) to the corresponding ester-acid 2 with preservation of optical purity. A number of suitable reagents and reaction conditions for accomplishing this goal will be discussed. The present investigation also sought to develop an accurate and convenient assay for determining the enantiomeric excess of compounds 1and 2. Although ¹NMR can be used for this purpose, it was found that GC-MS offers a number of distinct advantages. A comparison of the two analytical procedures will be presented.