References:

Fairweather, K. A.; Mander, L. N. Org. Lett. 2006, 8, 3395-3398

Jung, M. E.; Allen, D. A. Org. Lett. 2008, 10, 2039-2041.

Ireland, R. E.; Hengartner, U. J. Am. Chem. Soc. 1972, 94, 3652-3653.

Conclusions: In this article, the authors were trying to create trans-syn-trans- Perhydrophenanthrene Derivatives for steroidal antibiotics. They first created a syn-trans- enedione and then turned both ketones into ketals in order to create cis-syn-trans- Perhydrophenanthrene and trans-syn-trans-Perhydrophenanthrene. The reaction was a successful stereoselective reaction scheme that had a high yield.

Cited Papers:

Konstantinova, O.; Sarabèr, F. C. E.; Melguizo, E.; Jansen, B. J. M.; Groot, A. Tetrahedron 2006, 62, 1749–1755.

They were using Ireland’s article to do a one-pot annelation of two 6-membered rings, and referenced Ireland’s article and the method of making these syn-trans ene-diones. The idea was to be able to use Ireland’s method to be able to anneal two 6-membered rings similarly.

Peng, F.; Danishefsky, S. J. Tetrahedron Lett. 2011, 52, 2104-2106.

They added a “strategic” hydrogen atom via NaBH4 to a ketone, which they called an A- B trans-fusion. This allowed them to effectively manipulate molecule 19 into the target product 6. This is important because it directly relates to the article that we are currently reading about the total synthesis of Maeocrystal V.

Dai, M.; Krauss, I. J.; Danishefsky, S. J. J. Org. Chem. 2008, 73, 9576–9583.

Here, the authors were unable to use the Ireland-Claisen arrangement to effectively transform their molecule 11. Even the different protocol they ended up using still had a complete lack of diastereoselectivity that they were unable to change.