U-M CHEM 216 - Honors Cup Synthetic Proposal

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Honors Cup Synthetic Proposal Section: 231 Group Members: Andrew Lewandoski, Brian Meredith, Phil Yun Title: A Three Step Synthesis of Colletochlorin D Introduction: (what makes your target interesting?) Colletochlorin D is one of 4 molecules found in a fungus that causes a disease of the tobbacco plant. We liken this process to the synthesis of a poison or disease-causing agent, but one not dangerous to us. Overall synthetic reaction scheme: (a Chemdraw or similar drawing of all three steps) OHOH OHOHCHOOHOHCHOClOHOHCHOClstep1step 2step 3 Step 1: Zn(CN)2, Et2O, HCl Step 2: SO2Cl2, Et2O, 0degreesC Step 3: 1-bromo-3-methylpenta-2-ene, KOH, H2OStep 1 Synthetic transformation 1: (Chemdraw picture of first transformation) HOOHHOOHCHOa a: Zn(CN)2, Et20, HCI Experimental 1 (notes if this transformation is not exactly the one reported in literature (e.g. on a different scale) and how it was modified): Add 5g orcinol to solution of ether (125ml) in round bottom flask. Then add 1 mol equivalent of zinc cyanide (3.66g) and stir for .5 hours. Dry HCl added and the product then separates into oil. After 10-30 min, oil turns to solid. Add water to product to decompose HCl. Let sit overnight (or more) and then filter product. (this entire process is known as the Gattermann process, and can be found online.) Expected yield: 76-85 % 3.36g Safety, disposal and green issues 1: Safety issues for this involve the use of dry HCL. Be sure to use this in the hood. Disposal of the products should be done very carefully and into correct containers. In addition to this, the students involved in synthesis should be properly dressed and very careful during the lab.Step 2 Synthetic transformation 2: (Chemdraw picture of second transformation) OHOHCHOOHOHCHOClb b: SO2Cl2, Et2O, 0°C Experimental 2 (notes if this transformation is not exactly the one reported in literature (e.g. on a different scale) and how it was modified): In a round-bottomed flask, the aromatic aldehyde (1.11g, 7.3mmol) formed in experimental 1 is stirred into solution in dry ether (125mL) in a ice water bath. Sulfuryl chloride (1.08g, 8mmol) is dissolved in dry ether (25mL) and added dropwise into the stirred solution. The reaction is stirred for 1.5 hours in the ice water bath, and then at room temperature for 3 hours. A TLC (hexane:EtOAc, 6:1) is then run to assess the disappearance of the starting material. The solution is then washed with NaHCO3, saturated NaCl solution and water. It is dried over MgSO4, filtered, and concentrated in vacuo. The product is then separated via flash column chromatography with 15% ethyl acetate in hexane as the eluant. *Altered the time of stirring in room temperature from 8 to 3 hours. This may result in a slightly smaller yield than expected. Expected yield: 76.5 % 1.14 g Safety, disposal and green issues 2: Make sure gloves, goggles, and close-toed shoes are worn at all times while working with chemicals. Dispose of gloves and other solids in the solid waste container. All reactions should be carried out under a hood.Step 3 Synthetic transformation 3: (Chemdraw picture of third transformation) OHOHCHOClOHOHCHOClc. c: 1-bromo-3-methylpenta-2-ene, KOH, H2O Experimental 3 (notes if this transformation is not exactly the one reported in literature (e.g. on a different scale) and how it was modified): Add the product from step 2 (about 1.14g) in 4 mL of THF to a slurry of 30% Ba0-A1203 powder in dry ether. Evaporate the solvent and add 1-5 equiv of the allylic halide in ether-hexane (30-100%). A week later, filter off the solid and wash it with 1% HOAc-EtOAc. Evaporate or purify the organic layers by chromatography or crystallization. Expected yield: 42% (.5 g) Safety, disposal and green issues 3: Reactants and reactions should be handled with care under a hood. Tetrahydrofuran is very flammable and it’s fumes can be dangerous, keep away from head and flames. There does not seem to be any out of the ordinary problems with disposal.Overall budget: Chemical Supplier Cost Amt. Needed Total Orcinol Aldrich $3.30/g 5g $16.5 Zinc Cyanide Aldrich $0.12/g 3.66g $0.43 Ether Aldrich $0.04/ml 175ml $7 Sulfuryl Chloride Aldrich $0.04/g 1.08g $0.043 Total costs per synthesis: 23.93$ References (include at least two different sources for your experimentals): 1) Chen, K.; Joullié, M. Tetrahedron Letters. 1982, 23, 4567-4568. 2) Heinz Gluesenkamp, Karl; Buechi, George. J. Org. Chem.; 1986; 51(23); 4481-4483. 3) Safaryn, J. E.; Chiarello, J.; Chen, K. M.; Joullie, M. M. Tetrahedron Letters. 1986, 42,


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U-M CHEM 216 - Honors Cup Synthetic Proposal

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