ORGN 688 |
| The Wittig reaction has been widely employed and studied over the last 40 years. This reaction has been conducted in an array of conventional often toxic organic solvents ranging from the less polar such as benzene and toluene to more polar solvents such as DMSO, THF, or DCM. We present water as an excellent medium for the Wittig reaction resulting in numerous high yielding products as well high E/Z-ratios (up to >99:1). The reactions presented are compared to those reactions conducted in conventional organic solvents including alcohols. The reported reactions can either be conducted using stabilized ylides in water or mixing aldehydes with triphenylphosphine and alpha-bromoesters in a bicarbonate solution. This presentation demonstrates that solubility of the reagents is not of paramount importance, even though pronounced hydrophobic entities are present. The reported aqueous Wittig conditions have also been used to prepare a key fragment of a streptogramin antibiotic, Virginimycin M1.
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New Reactions and Methodology
1:00 PM-5:00 PM, Wednesday, 13 September 2006 Moscone Center -- Room 133, Oral
Division of Organic Chemistry |
