Question

Predict the products for the following resctions. - Please explain how you know as I am struggling with the mechanisms if the reactions are not E2 or Sn2.

5) Predict the products for the following reactions. Do 8 of 9, one will be extra credit. (34 points) Me;coº CH,CH OH 06 H₂ CH3CH2OH

Answer 1

r/preduct and te yoy tirst I ill give you only answer the mechanism it is fllowing Then I will give yoy a ehart. After analyzing the chart You wil1 be able to in de ntify mechanism easily OH SN (beaue primary halide and Goed nueleephile) a) OH E secendry halide streng hase EZ H20 qct 4s weak basc SN primary hatide geed uclecphile) CN E (Polar pre tis selvent CH, CH, OH Sign of heat A eliminahon) means

Ace jorganic SN1? E1? SN2? E2? How Will I Know?? Chem.com What are the reactions? Nu- Nu- Base Base SN2 E1 E2 Compare each of the criteria on this chart. See which reaction has the most factors going for it. SN1 E1 SN2 E2 2-step w/a carbocation 2-step w/ a carbocation Reaction Concerted Concerted mechanism Strong, non-basic, non Can be mediocre, must be basic Strong AND basic Strength of nucleophile Can be mediocre, must be non-basic bulky Must be great Leaving group ability Must be great Can be mediocre Can be mediocre Polar Protic Polar aprotic Solvent Polar Protic Polar aprotic Favored only w/ a strong Primary Substrate Highly favored No reaction No reaction base Only w/ a non-basic nucleophile or if the Favored with strong base Secondary substrate Only if the carbocation is resonance stabilized Need strong non-basic nucleophile, otherwise will compete with E2 carbocation is resonance stabilized Tertiary substrate Favored with non-basic Competes with SN1 No reaction Can occur but ONLY with nucleophile a strong base "H" must be able to go Stereochemistry gives (almost) totally racemic product, see #2 Bulky groups will prefer Walden inversion antiperiplanar opposite sides below What are the nucleophiles? What are the leaving groups? What are the solvents? What are the bases? VERY GOOD Nu: F, HS", RS Good Nu: Br, HO, RO, CN, N Fair Nu: NH, CI, F, RCO2 Weak Nu: H,0, ROH VERY Weak Nu; RCO,H Polar Protic: Acetic acid, H,O, ROH, NH Great: I, Br Cl-OTs, OCF OMs, and H,O (not OH) Mediocre: F, CH,coo, NH (not NH,) Very Strong: NH2, H, HCEC Strong: RO, HO, Polar Aprotic: DMF nitromethane, acetone, Mediocre: RNH, Na CO Weak: NH2 CN RCOO, Cl, Br E, NaHCO acetonitrile, DMSO, ethyl acetate Bad: OH-, OCHs, NH Non-polar: alkanes, cycloalkanes, toluene, benzene, ether. And don't forget.. .. 1) Carbocations WILL rearrange if they can 2) Solvent-Separate lon Pairs (SSIP) Keep SN1 rxs from being completely racemic 3) E2 need antiperiplanar H's, or no rxn. S-0 180 LG Nu- Nu- Sightly favored here The leaving groups partially blocks one face, keeping it from being totally racemic. Will rearrange to a more stable cation. Must be able to rotate the H into a 180° angle or no rxn. Can happen with rings sometimes.