It’s much harder to write when the coffee hasn’t made it across the goal line, but since I went into the utility of microwaves for chiral endeavors, I thought I should probably add a few more reasons why:

Here is a recent example (Molecules 2011, download pdf) of an improved method for making Evans oxazolidinone auxiliaries, or even analogs to be tried. If you don’t care as much about the aldol part, remember these heterocycles are found in a healthy number of antibiotic drugs. So much better for me than writing about Felkin and anti-Felkin selectivity this morning.

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mw: Amino alcohol and diethyl carbonate, mild base

In case you want to compare with conventional methods (oh yea, the caffeine is kicking in):

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Conventional v. MW

Expanding the route to include oxazolidine-2-thiones and thiazolidine-2-thiones gives some other possibilities to look at additional routes (one example had an inversion of stereochemistry by the end of the conversion, interesting— I believe some of these have shown equal or better selectivities.

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MW: Oxazolidine-2-thiones and thiazolidine-2-thiones

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Table: mw v. conventional

Chiral diazaborolidine substrates have been used for asymmetric reduction of (pro)chiral ketones ( I always thought that was a funny term).

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Reported use of diazaborolidine in chrial reduction

However, this group could not reproduce the formation of a similar reagent (to 10) under classical reflux conditions. Modification to microwave conditions provided the reagent.

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mw formation of chiral diazaborolidine

That seems about an espresso’s worth of microwave action for this morning. Enjoy the day.

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