[meaningfulgibberish]

I've been running this reaction for a couple months now. I take N,O-dimethylhydroxylamine salt, add to it either DIBAL or Trimethylaluminum, then add that solution to a solution of a lactone. Work-up consist of quenching any small amount of DIBAL left, acidification to pH 3-4, then overnight stir in Potassium Sodium Tartrate. Previous grad student would typically get anywhere from 30%-40%. I'm at best getting 20%.

Does anyone have any experiences with these reactions? What are some things I could do to improve yield? I know synthesis can be frustrating but this is beginning to be ridiculous.

[discodermolide]

What is the rest of the material? Starting material or what?

[meaningfulgibberish]

At times I'll get a small amount of starting material back, but the mass balance wouldn't make sense if it was a conversion problem. I'm not getting enough starting material back to say that it is a conversion problem. My other guess is that my product may still be stuck on the aluminum. It would explain the drop in yield when I'm using tartrate in my work-up. But then if that's the case, why is it still on there?

[discodermolide]

Try using acetic acid quenches. But be careful, keep it controlled. The Rochelle salt may not be enough to remove all the Al, I have had better results, in different systems, with acetic acid.

[meaningfulgibberish]

I'll give it a shot. Thanks!

[Dan]

What to you have planned for the Weinreb amide product? I ask because morpholine might be a better choice, see:

http://www.sciencedirect.com/science/article/pii/S0040402014003792

[meaningfulgibberish]

What to you have planned for the Weinreb amide product? I ask because morpholine might be a better choice, see:

http://www.sciencedirect.com/science/article/pii/S0040402014003792

This looks great! I use the weinreb amide to make a ketone. The grignard addition works fine, but this looks like a much better alternative. Thank you!