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

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.


Ingredients
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

Method
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.

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.

ASAP Friday

A couple of ASAP articles from JACS stood out for me this morning.

The first is an interesting Nazarov cyclization followed by a Wagner-Meerwein rearrangement reported by Alison Frontier. Depending on the substitution, the path of the Nazarov is altered and the reaction is terminated by either a hydride shift or an aryl shift. Interesting paper well worth reading the details.

Jie Huang and Alison J. Frontier, JACS DOI: 10.1021/ja0716148

Mukund Sibi reported a novel organocatalytic method for the conjugate addition of hydroxylamines. The catalyst provides for both hydrogen bonding activation of the substrate and hydrogen bond-directivity for the incoming nucleophile.

Mukund P. Sibi and Kennosuke Itoh, JACS DOI: 10.1021/ja071739c

I have returned

I have returned to the US after spending a little more than two weeks in France. I enjoyed food, wine and chemistry during my visit. I was very fortunate to taste some excellent wine including the bottle you see to the right! It was amazing. Was it worth the price? Well, in my opinion, no wine is worth that much, but it truly was exceptional. I am now playing catch up with all the work that was left undone here.

I suppose on a chemistry blog, I should post some chemistry. Among the plethora of fine literature contributions I missed while I was gone was this interesting organocatalytic cascade reaction reported by List.

Jian Zhou and Benjamin List JACS ASAP. DOI: 10.1021/ja072134j

Chimie

Please pardon my lack of posts. I'm traveling in France for a couple of weeks and haven't had a chance to write anything. I visited l'École Nationale Supérieure today. I was able to see original research samples from Louis Pasteur. What a treat!

Odeur d'Asperge

Yes, it is asparagus season. I love this vegetable. Raw straight out of the garden, steamed with white wine and garlic, coated with olive oil and roasted on the grill, I can't get enough of it! Of course, for some of us that means plenty of malodorous urinary discharge. Yes, I'm talking about the infamous Asparagus Pee! The culprit - Asparagusic Acid. Derived from valine, this acid is unique to asparagus and appears to be the metabolic precursor to a number of odiferous sulfur-containing compounds. In its pure form, this colorless solid melts around 76 °C. For those with the enzyme to break it down (~40% of the population) the results appear in the urine usually within 15 minutes of ingestion. Interestingly, not everyone has the ability to smell the satisfying stench, thus complicating studies to determine why some have smelly piss and others do not. I am one of the lucky ones who can both produce copious quantities of metabolites such as methyl thioacrylate (among others) and delight in its pleasing perfume. For those of you deprived of this evolutionary gift, I have sympathy, as you will never truly enjoy the full experience of asparagus season. (edited 5/8/07, 5:28 pm to fix structures)

Your Road to a PhD

I'd like to call out some of the lurkers who read my blog to come forward and make some comments. I'm curious to find out what influences a student's decision for choice of graduate school in chemistry. So, if you have your PhD, are in a PhD program now, or going to join a PhD program soon, please tell me what was important for your choice of school. Was it location? Science? Stipend? What? Did family issues change your decision? Would you only look at schools on the coasts, or did you look across the middle of the country too? How influential were your undergraduate mentors? What about international studies? This would apply to those from the US going abroad as well as those from outside the US coming to America. And finally, what sources did you use to find graduate programs? Do you put any stock in the web sites that list rankings of graduate programs?

A Rhodium Thing

Ever since my first encounter with aldehyde C-H insertion by rhodium, I have been intrigued by the possibilities of the acylorganometallic intermediates. In Org. Lett. a nice formal [4+2] cycloaddition appeared utilizing ortho-vinyl benazaldehydes and olefins or alkynes. The reaction proceeds via C-H insertion to form an acylrhodium followed by a migratory insertion to produce a rhodacylopentene. This reacts with an alkene to form the product shown. Chiral ferrocenyl phosphine ligands afforded at least modest level of enationselectivity. If alkynes were utilized, napthol products were produced. Although most yields and selectivities were modest, it is an interesting transformation. It seems to be limited in scope. Without the arene ring cyclization did not take place. Instead the acylrhodium simply reacts with the olefin in a reductive Heck-type process to afford an acyclic ketone.

Ken Tanaka, Daiki Hojo, Takeaki Shoji, Yuji Hagiwara, and Masao Hirano, DOI: 10.1021/ol0704587

Cross Coupling of Anilines

A fascinating paper appeared on the JACS ASAP site this morning from Ueno, Chatani and Kakiuchi. They used a ruthenium catalyst to carry out a cross coupling of an aryl amine with a phenyl boronate. What is remarkable is the fact that the transition metal did oxidative addition to an aryl-nitrogen bond. Success of the reaction was dependent on having a chelating carbonyl group adjacent to the amine, however, this is still the first example of oxidative addition to a hitherto unreactive C-N bond.

Satoshi Ueno, Naoto Chatani, and Fumitoshi Kakiuchi, DOI: 10.1021/ja0713431