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U of M CHEM 210 - Key 2

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I. (40 points)hybridization electronic geometry observable geometryatom O1atom O233Name _______________________Page 1sp2sp2trigonal planartrigonal planarbentbentall three answers must be right for the row = 3 no partialatom O33sp3trigonal planartrigonal planaratom C3sp2tetrahedral(j) Analyze the geometries and hybridizatios for several atoms in (+)-catechin.Catechins are natural compounds, produced by plants and containing antioxidant and antiseptic properties. Shown below is the molecule known as (+) catechin.(S)(S)(R)(R)OOOOOOHHHHH(+)-catechin(S)(S)(R)(R)OHOOHOHHOHO(a) Circle the longest C-O bond(s) in (+)-catechin.(b) Put a box around the longest O-H bond(s) in (+)-catechin.(c) Identify and give stereolabels to all tetrahedral chiral stereocenters in (+)-catechin.[α] = +1422only one4For each of the options below circle the best answer about optical activity.(f) This compound's optical activity would be:(+14)(-14) 0 can't tell(R)(R)(S)(S)OHOOHOHHOHO(R)(R)(R)(R)OHOOHOHHOHO(g) This compound's optical activity would be:(+14)(-14) 0 can't tell(h) This compound's optical activity would be:(+14)(-14) 0 can't tell33 3(e) (+)-catechin would have (put the correct number in each of the boxes).3stereoisomerschiral diastereomersoptically inactive diastereomers320(d) (+)-catechin contains (put the correct number in each of the boxes ).3aromatic rings units of unsaturationunhybridized p orbitals2917bent(i)(+)-catechin's most acidic proton has a pKa of about 9. Circle the bases that can deprotonate the most acidic proton with a Keq > 104.NOOONKONaNa174.85.236NH24.65all three and only those - no partial creditNa19O1O2O3OOOOOOHHHHHC2 pts each1 pt each1 pt eachName _______________________Page 2II. (41 points)A.Provide the missing information for each of the following syntheses. Be sure to number reagents when multistep transformations are required. When stereoisomeric products form, please draw one and state "+ enantiomer" or "+ diastereomer" to indicate the other.B.NO2Cl2) HNO31) H2SO4SO3HXFeX31)2)OClAlCl3O342 pts each step, must be in right order - if perfect but switched: 2pts / if not numbered 0ptsCl4C9H13ClC9H15Cl3H2Pd CaCO3 (or BaSO4)PbO (or quinoline)N HIonic product(s)ClNH41ptSOClONOOH1)C C CH3LiOCH32)OCOrganic product(s)CCH3CH3Cl1)2)Li44OOCH3Balance the reactionsC.Li ClCH3OH1pt1pt2 ptsBrClOOOH(S)(S)Br(R)(R)(R)(R)O(S)(S)Br(S)(S)(S)(S)OOR+ diastereomer41ptBrBrBrLiCN4Balance the reactionLiBr1pt1pt2 pts(S)(S)CN(E)Br+ enantiomerNC(R)(R)(E)BrD.ORE.ONHBr2ONONHBr1 equivalentAlCl3Single major productOLiLiOHBalance the reaction1pt2 pts1pt34SOOONH1pt1pt2 ptsorganic must be correct for the other ptsorganic must be correct for the other ptsorganic must be correct for the other ptsorganic must be correct for the other pts - watch connectivity of CNONalso valid drawingHNO3 = HONO2must be meta to each otherif numbered - 2ptsName _______________________Page 3III. (39 points)B.a diastereomeric pairan enantiomeric paironly chiral molecules1 unique moleculeX3 or more stereoisomeric moleculesThis connectivity representsonly achiral moleculesa diastereomeric pairan enantiomeric paironly chiral molecules1 unique moleculeXX3 or more stereoisomeric moleculesThis connectivity representsonly achiral moleculesa diastereomeric pairan enantiomeric paironly chiral molecules1 unique moleculeX3 or more stereoisomeric moleculesThis connectivity representsonly achiral moleculesFor each of the following connectivity drawings check all the descriptions that apply.(a) (b)(c)333all or nothingall or nothingall or nothingFor each of the following pairs, choose all the descriptions that apply; write the letters corresponding to those descriptions in the box with the pair of drawings.(S)(S)(R)(R)(S)(S)Br(E)(S)(S)(R)(R)BrBr(Z)(S)(S)HHCH3HC) are structural isomersB) are diastereomersA) are enantiomersG) represent at least one optically active compoundF) contain at least one R stereocenter (in the pair)1 and 2:D) are conformational isomers (conformers)E) are identical molecules12HHCH3H563 and 4:347 and 8:78910C GA F G39 and 10:E D G(R)(R)(S)(S)(S)(S)HO(S)(S)OHNNB F G5 and 6:B F G3333BrHOOHHHCH3HCH3HHH(s) on both chiral centersA.Rearrangements can occur when other unstable intermediates are formed. In the reaction shown below, the formation of a chloronium ion intermediate leads to ring expansion and a resonance-stabilized carbocation which is deprotonated to yield a neutral product. Draw this 3-step mechanism; be sure to show/use the best carbocation intermediate.OHOClOHClstep 1OHClstep 2OOClOHstep 3C.tert-butyl hypochlorite is a source of electrophilic chlorine15OClClXgreen arrow optional - goes to best resonance form3 pts each intermediate3 pts each mechanistic step (all arrows must be correct)grading stops at first irrational stepName _______________________Page 4IV. (42 points)A.In each of the following reactions more than one product is formed. Draw each product in its appropriate box (each reaction yields at least one product of each category) and provide some analysis of the starting material, as requested. Major regioisomers only! Be sure to show all structural and stereochemical properties unambiguously.H2OH2SO4 (cat.)C.B.optically inactiveproduct(s)optically activeproduct(s)62 each, must be in correct boxesComplete name (including stereochemical label(s)) for A:4AD.6Coptically inactiveproduct(s)optically activeproduct(s)63 each13C NMR signal(s)1H NMR signal(s)The NMR spectra for D would show :(write in the number)223E.63 pts each pair, must be in correct boxes13C NMR signals: 8The stereoconfiguration(s) for E1OHOH(S)(S)(S)(S)OHHOHO(S)(S)(E)H(R)(R)OCH3Clif ALL correct products ARE PRESENT but switched boxes: 3 pts onlyif ALL correct products ARE PRESENT but switched boxes: 3 pts onlyif ALL correct products ARE PRESENT but switched boxes: 3 pts onlyif ALL correct products ARE PRESENT but switched boxes: 3 pts onlyIF STEREOCHEM IS NOT SHOWN, NO CREDITBr2/FeBr313C NMR signals: 6HOCH3ClBrHOCH3ClBrROHHO(S)(S)(R)(R)OHHOOptically active diastereomersC has :(write in the numbers)220Optically inactive diastereomers(S)(S)(S)(S)(S)(S)(R)(R)Br2Product(s) after one equivalent of Br2and after excess(E)BrBrBr2BrBrBrBr(S)-cyclobut-2-en-1-olH2 (excess)Pd/CB(E)(Z)DEProvide stereochemical label(s) for B3(R)(R)1) O3 (excess)2) H2O261H NMR signals: 51H NMR signals: 3OHOOO(R)(R)O1 stereo3 all the rest1pt each3 pts3 each3 eachName _______________________Page 5V. (38 points)A.C.A nitrilium intermediate may promote electrophilic


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