5.451 F2005 Problem Set 3. 1. (25 pts) Using your knowledge of the 20 proteogenic amino acids, propose the startingmaterial as well as a mechanism of biosynthesis for the following alkaloid. General acid bases catalysis and an oxygenase reaction is utilized. HN NH 2 O H H NHHN OH OH Professor Sarah O'Connor Massachusetts Institute of Technology5.451 F2005 Problem Set 3. 2. (25 pts) Propose 3 naturally occuring starting materials and a mechanism (using general acid/base catalysis) for assembling them to yield the following alkaloid. N H O O H HN NH Professor Sarah O'Connor Massachusetts Institute of Technology5.451 F2005 Problem Set 3. 3. (25 pts) A-E. Monoterpene biosynthesis. Draw the mechanism of biosynthesis for eachof the following monoterpenes starting from geranyl diphosphate. Include all intermediates and utilize arrows to indicate the flow of electrons. These reactions are enzymatically catalyzed by a terpene cyclase, so utilize general acid/base catalysis. A B C D E OH Professor Sarah O'Connor Massachusetts Institute of Technology5.451 F2005 Problem Set 3. 4. (25 pts) Sesquiterpene biosynthesis. Propose a detailed mechanism of biosynthesis fromfarnesyl diphosphate for the following unusual sesquiterpene. (The last step thatconverts the intermediate to the final product is not typically observed in terpenebiosynthesis.) terpene farnesyl cyclase [intermediate]diphosphate Professor Sarah O'Connor Massachusetts Institute of