Please Help! How do I convert (r)-2-butonal to (s)-s-butonal using toluenesulfonyl chloride tosyl chloride (tsCL) as a replacment leaving group sense -OH is such a poor leaving group. I can normal preform this kind of reaction, if the nuclelophil is different than the orginal leaving group. I got to the point where i have (R)-2-butyl tosylate. The leaving is TsO- I want to convert this into HO-. How should I do this? Should I add an protic acid, or Na OH. BTW why do SN2 reaction invert the configuration. I am having a hard time visualling why they invert configuration.