Thursday, August 27, 2009

Mary Watson, University of Delaware


Mary Waterson,
BS, 2000, Harvard University, phd, 2006 with Larry E. Overman, 2006–2009, postdoc with Eric N. Jacobsen. During her postdoc, she developed a nickel-catalyzed method for olefin arylcyanation via activation of C–CN bonds. She joined the faculty at the University of Delaware in July 2009.
Research:
centered on the discovery of new catalytic, stereoselective methods for organic synthesis by utilizing the power of both transition metal and Brønsted acid catalysts.
1. Selective Activation of Relatively Strong Bonds
C-H activation.
2. Brønsted Acid-Catalyzed Reactions of Unactivated Olefins
enantioselective additions of H–X (X = C, O, N, etc.) across olefins.

publication:
pending

Thursday, August 20, 2009

A proposal of synthesis of maoecrystal V

In 2004, islolated was the maoecrystal V with a novel C19 skeleton from the leaves of a Chinese medicinal herb, Isodon eriocalyx. it is remarkably active against HeLa cells (IC50) 0.02 ug/mL).
The two chiral quaternary carbons and a tertiary alcohol in a contiguous setting served to pose interesting challenges to the science of chemical synthesis.
So far, no total synthesis. the following are just my thoughts.











another one. not better.










or umpolung chemistry.(sorry, one methyl is missing in the product).

Monday, August 17, 2009

what can you do if your precious compound spilled?

My precious compound spilled out of a bottle and sticked onto a piece of plastic foam. the foam was dissolved by the dcm which is the solvent with my compound.
Discard it ? no, the boss will kill me.

1 I cut the foam off and dissolved the foam (with my compound) with DCM/EtoAc.
The foam dissolved without problem. concentrated. passed a pad of silica gel, eluting with etoac, nothing can be removed.
2. checked the structure of the foam through internet, it is polystyrene,
http://en.wikipedia.org/wiki/Polystyrene
tried to run a TLC with pure polystyrene, no obvious spots.

3. tested the solubility of the foam in organic solvents.
soluble: dcm, etoac, ether
unsoluable: meoh, hexanes,
4. so meoh was added to precipitate the polystyrene, and a simple filtration with silica gel removed the plastic.

Friday, August 7, 2009

The radical reactions of imine radicals

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Tetrahedron
Volume 65, Issue 36, 5 September 2009, Pages 7415-7421

In conclusion, imine radicals 5 and 15 can be generated from the manganese(III), silver(II) oxidation of 2-amino-1,4-benzoquinones. These free radical reactions provide efficient methods for the generation of the dimeric products 4 and 14. In the presence of styrene, twistane 17 was afforded from 2-phenylamino-1,4-benzoquinone 1 via a radical annulation reaction of imine radical 5.


















mechanism:

Wednesday, August 5, 2009

Peptide–Dirhodium Ligation

Controlling Peptide Structure with Coordination Chemistry: Robust and
Reversible Peptide–Dirhodium Ligation
DOI: 10.1002/chem.200901266
Chem. Eur. J. 2009, 00, 0 – 0

interesting paper.

A novel iodine-mediated tandem cyclization

Chem. Commun., 2009DOI: 10.1039/b910232a

A novel iodine-catalyzed tandem cyclization–cycloaddition reaction of ortho-alkynyl-substituted benzaldehydes leading to polyoxacyclic ring systems has been developed, which represents a useful approach towards the synthesis of the oxabicyclo-[3.2.1]octane ring skeleton found in a variety of natural products.


mechanism:

Saturday, August 1, 2009

Stereoelectronic Effect for the Selectivity in C−H Insertion of Alkylidene Carbenes

Stereoelectronic Effect for the Selectivity in C−H Insertion of Alkylidene Carbenes and Its Application to the Synthesis of Platensimycin

Sang Young Yun, Jun-Cheng Zheng and Daesung Lee* Department of Chemistry, University of Illinois at Chicago, 845 West Taylor Street, Chicago, Illinois 60607-7061J. Am. Chem. Soc., 2009, 131 (24), pp 8413–8415DOI: 10.1021/ja903526g


High selectivity in the insertion between two competing C-H bonds was observed and is believed to be the manifestation of a strong stereoelectronic effect of oxygen substituents.