Monday, July 23, 2007

An Alkene Zipper Reaction

Aaron over at Carbon Based Curiosities has recently posted about one of my favorite reactions, the alkene zipper reaction catalyzed by 1,3-diaminopropane and potassium hydride. Most of the time this reaction works great, but it is thermodynamic and has some problems when your alkyne is stabilized by conjugation. Anyway, an interesting paper appeared on the JACS ASAP web site last week dealing with the alkene version of a zipper reaction. It is a very nice contribution from Doug Grotjahn and co-workers from San Diego State University. It utilizes a bifunctional ruthenium catalyst to walk an alkene down the chain until it reaches an alcohol. Once an enol is generated it quickly tautomerizes to the ketone form thus providing the thermodynamic sink for the reaction to fall into. The imidazole ligand on the catalyst was crucial for success and may be involved in the isomerization. A very interesting example of this difficult to accomplish process.

Douglas B. Grotjahn, Casey R. Larsen, Jeffery L. Gustafson, Reji Nair, and Abhinandini Sharma: JACS 2007, DOI: 10.1021/ja073457i

Friday, July 13, 2007

Lila's Pasties

Taitauwai, from the Chemistry & Cooking blog, prompted me to post off topic. I guess most organic chemists like to cook, myself included. Anyway, in the comments to my last post I mentioned that I still make my Grandmother's pasty recipe and Taitauwai asked for the recipe.

If anyone has been up to copper country in the upper peninsula of Michigan, you have undoubtedly encountered pasties. These are meat and potato pies that originated in England. During the early 20th century the Keewenau Peninsula was the world's richest source of copper and immigrants from Finland and England mined the ore. The pasty became a staple food for the miners. My grandfather was a copper miner and my grandmother Lila would make these wonderful treats for him to eat at work. The miners loved them because they could hold them in their hands to eat. This is as close to my grandmother's recipe as I can get, although I suspect she used shortening or lard in the crust instead of butter. I prefer them slathered with ketchup.

Serves 8

The Crust
3.5 cups flour
1.5 cups cold butter
1 tsp salt
~0.5 cups ice water

The Filling
2 lb ground chuck or other ground beef
4-5 medium potatoes
4-5 large carrots
1 medium rutabaga
1 large onion
salt and pepper to taste

preheat ove to 375°F

The Crust
Mix the flour and salt. Cut in the butter (I use a food processor pulsing for about 10 seconds) to make a mixture the consistency of lumpy gravel. Add water by the teaspoon and toss just until the dough can be formed into a ball. Wrap with plastic wrap and refrigerate for at least 3o minutes. I like to divide the dough into four balls and slightly flatten them when I refrigerate. This dough should make 8 good sized pasties.

The Pasties
Dice or shred all the vegetables and mix with the meat. Season to taste. Divide the dough into eight and roll them out one at a time into a round oblong shape. Place a mound of the filling on half of the dough and fold over, sealing the edges with a little bit of water and pinche them together. I like to twist and fold the edges up to make the edge a bit more decorative. Place on an ungreased baking sheet and bake for 50-60 minutes, until the crust is nicely browned. Serve with ketchup or butter.

Monday, July 9, 2007

Summertime Light

I'm back after a bit of an absence. Summer has been very busy and I did take a little time to head back to my home state of Michigan for some camping. One thing I rediscovered was the joy of fireflies. We don't have them where I live now, but I remember the lazy late summer days of my youth chasing and catching these wonderful creatures. They are out in force this year glittering and lighting up the summer nights. Of course this leads to chemistry and not just nostalgic blatherings. As a kid I was fascinated by how the light was produced and we owe it all to a little molecule called Luciferin. In the presence of Luciferase and ATP, an AMP-modified luciferin is produced. This, in turn, reacts with oxygen to produce oxyluciferin in the excited state. Relaxation to the ground state produces the all too familiar orange-yellow glow of the firefly. Nature comes up with some unique ways for males to attract mates, and this is one of the more interesting ones.