From Prof. Mark A. Forman's group at Saint Joseph's University, Philadelphia
I have to admit that I have not read this article closely, only skimmed through it and thought some of the materials worth blogging about, especially the novelty of the synthesis and some of the chemistries performed on the pentacycle. Also, the schemes and charts should be easily understood. This article recently appeared in JOC ASAP.
The highly pyramidalized alkene, pentacycle 9 was synthesized and its reactivities were studied. The plan was to make diiodide 12, then perform Li-halogen exchange and LiI should eliminate to give 9. The synthesis started with norbonadiene, see the scheme below.
Key of Reactions: (a) dimethylacetylene dicarboxylate, MeOH, heat, 73%; (b) KOH, MeOH, H2O then 10% HCl, 97%; (c) light, diethylether, 25%; (d) DCC, THF; (e) NaOMe, MeOH, 98% 2 steps; (f) (i) (COCl)2, CH2Cl2, DMF, (ii) 2-mercaptopyridine-N-oxide sodium salt, benzene, 2-iodo-1,1,1-trifluoroiodoethane, DMAP, 66%; (g) KOH, MeOH, H2O then 10% HCl, 94%; (h) (i) (COCl)2, CH2Cl2, DMF, (ii) 2-mercaptopyridine-N-oxide sodium salt, benzene, 2-iodo-1,1,1-trifluoro-iodoethane, DMAP, 53%.
After diiodide 12 was successfully synthesized, it was subjected to several different reactions as shown below. First, the treatment of 9 with 10.
Treatment of 9 with n-BuLi.
Compound 9 could also be trapped with 1,3-diphenylisobenzofuran (DPIBF) to give 27. 
In this case, t-BuLi did not add across the double bond in 9, like in the case of n-BuLi. Alkene 9, generated by t-BuLi was also trapped with other dienes.
Later on, the molecular calculation of alkene 9 was conducted and several characteristic numbers from the calculation, including the calculation parameters, are shown in the following figure.
1 comment:
Nice brief and this enter helped me alot in my college assignement. Thanks you seeking your information.
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