REVISION PROBLEMS

Revision Problem 1 Leaf alcohol (TM 392) is widespread in plants and has the characteristic smell of green leaves and grass. The cis isomer alone has tlfis smell and is used in perfumery. How would you make it  

Analysis The olefin can come fi om an acetylene and so we are guided into our disconnections  

Synthesis Sondheimer (J. Chem. Soc.. 1950, 877) made leaf alcohol this way. 

Rerfision Problem 2 a-Terpineol also occurs widely in plants and was one of the first natural products to be isolated pure. There was originally some doubt as to whether its structure was TM 394A or TM 394B. Suggest syntheses of both these compounds so that they can be compared with the natural product. 

Analysis The strategy for any modem syntheses of these compounds would be based on the Diels-Alder reaction or the Birch reduction  

---

Whoever you are, you will certainly find discussion with your fellow students one way to get the most out of the programme and you may well find it is a good idea to work on the more difficult problems together. The review problems, revision problems, and problems without worked solutions are ideal for this. In some cases I have given references to the original hterature so that you can find out more details of the various possible approaches for yourself if you want to. It isn t necessary to look up any of these references as you work through the programme. 

Revision Problems For those of you who have aheady done all the review problems, there are some not too difficult revision problems in the next section. AU have answers. 

Problems in Strategy Our discussion on strategy was hmited to the more straightforward aspects. This section has some challenging problems without worked answers. These are more difficult than the revision problems. 

Revision Problem 3 House fJ. Org. Chem., 1965, 3 1061) wanted to study intramolecular Diels-Alder reactions and wanted molecules Uke TM 396 in which n is 3 or 4, so that the product will have a 5 or 6 membered ring if the reaction works. It would obviously be a good thing if the synthesis can easily be modified to make other size rings as well. What do you suggest ... 

Revision Problem 4 Musks are compounds which have some pleasant smell themselves, but function chiefly by retaining and enhancing the perfume of other compounds. How might celestoHde , a modem musk, (TM 398) be made ... 

Revision Problem 5 This molecule (TM 400) was used by Raphael in his synthesis of the natural product clovene. How could you make it. 

Revision Problem 6 CascariUic acid occurs naturally in Euphorbiaceae plants (spurges). How could you synthesise it ... 

Revision Problem 7 TM 404 was needed as an intermediate in a steroid synthesis. How might it be made ... 

Revision Problem 8 TM 406 is a synthetic intermediate related to the caimabinoids, naturally occurring hallucinogenic compounds. How could it be synthesised ... 

Revision Problem 10 This compound is an intermediate in the synthesis of an alkaloid. Don t worry about the half ethei aspect - there is a solution to this which will emerge as you go along. 

---