Don M. Coltart

http://fds.duke.edu/db/aas/Chemistry/faculty/don.coltart

Assistant professor, Duke
NSERC, AHFMR, and CRI Postdoctoral Fellow, Memorial Sloan-Kettering Cancer Center, 2001–2004
Ph.D. Chemistry, University of Alberta, 2000
M.S. Chemistry, University of Manitoba, 1995
B.S. Biochemistry, University of Manitoba, 1993

Research Interests

Asymmetric α-Alkylation of Ketones via Activated Hydrazones

Direct Carbon-Carbon Bond Formation via Soft Enolization of Thioesters

Natural Products Total Synthesis

A proposal for the synthesis of cortistatin A

The  proposal is as following:

The discussion of key steps:

1. the c-h insertion to form the five-membered ring is well known.

2. The oxygen bridge can then be formed through epoxidation and epoxide ring expantion which might be the biological way also.

3. alternatively the oxygen bridge can be formed by the diazo insertion into C=O and then 3+2 addition.

4.the 7-membered quadene can be constructed by carbene/carbenoid inerstion into aromatic rings followed by elimination of OAc.

Enantioselective Fp mediated alkene addition?

the above reaction is from wiki
http://en.wikipedia.org/wiki/Cyclopentadienyliron_dicarbonyl_dimer


I am just wondering whether it is possible to make it enantioselective?
anyone did it already? not as I know.

A proposal for englerin A synthesis

A hot molecular.
here I proposed a synthesis of Englerin A.

1. it is known we can open the epoxide from the more hindered/more stable site.

2. Single electron reduction then can form the required C-C bond and hopefully set the secondary alcohol.

The starting material can be prepared by C-H insertion. It is known to give trans fused 5,6 rings.

One method to enhance the power of the lab sonicator

Besides of getting a more powerful sonicator, there is a simple method you can try to get more power out of the old sonicator.
the method is described in a journal paper by a Japanese researcher.
The method is simple: just add detergent to the water bath.
The result is substantial.
the reason is ovbious that the polymer has big molecular weight than water so the long-distance energy-transfer-ability is better.

Don't believe ? try it! and post the result here.

Proposal of synthesis of mayamycin

Johannes Imhoff and co-workers at IFM-GEOMAR inn Germany have isolated a polyketide that had an IC50 value of 0.3 micromolar against HT-29 (colon adenocarcinoma) cell lines.

preparation of derivatives of Calicheamicin by enzyme ？

1. The gene for the biosynthesis of calicheamicin is known. As I can remember, the calicheamicinone is constructed and attached to a sugar by an enzyme.
2. Calicheamicin is cheap by biosynthesis. calicheamicinone is difficult to make by chemical synthesis.
3. no known way to cleave Calicheamicinone from calicheamicin.

So is it possible to make new derivatives by mixing a new sugar with calicheamicin in the presense of some enzymes ?