Reaction Halogenation Reactants Product Mark/Anti Intermediate Stereochem? Rearrange? None X on each side of bond Bridged ion Trans halides No Alkene X2 in apolar (CCl4, CH2Cl2) Alkane Dehydrohalogenation (E2) Alkane Alkene Zaitsev unless bulky, then Hofmann None Anti-coplanar (β hydrogen and LG are 180˚ apart) No Double Dehydrohalogenation Alkane Alkyne Mark None Unknown No Alkyne Alkyne Alkane None Bridged ion Trans dihalides No Halogenation X2 1 equiv. Tetrahalide (2 vicinal) 2 X on each side of bond Hydrohalogenation Vicinal dihalides Alkyl Halide w Base Dihalide w Bulky Base Alkene Alkane H—X Alkyl Halide Hydrohalogenation with peroxide Alkene Alkane HBr in ROOR Alkyl Halide Alkyne Hydrohalogenation Alkyne Alkane HX in excess Geminal Dihalide Conjugated Hydrohalogenation Diene Alkene HX Allyl Br/Cl Halohydrin Formation Alkene Alkane X2 in polar (H2O) X & OH Allylic Bromination Alkene Alkane Br2 in heat (Δ) or light Allyl Bromide Allylic Chlorination Alkene Alkane Cl2 in heat (Δ) or light Allyl Chloride X X X X Mark addition of halide Carbocation None Yes Anti-mark addition of halide Radical None Yes Mark addition of halide Carbocation None No None Carbocation None… but: Yes >40˚=1,4 product <0˚ =1,2 product Mark OH Bridged Ion Anti No Trans OH and X None Radical Chiral=Racemized Yes None Radical Chiral=Racemized Yes Reaction Reactants Acid-catalyzed Dehydration Alkane (E2 if 1˚ alcohol) Strong acid (H2O, ROH, HX in H2SO4, H2O, HgSO4) (E1 if 2˚ or 3˚ or can rearrange from 1˚ 3˚) Acid-catalyzed Hydration Product Alkene Alkane Alcohol Hydroboration Alkene Alkane Oxidation BH3, RBH, THF in H2O2, NaOH, OH Alcohol Alkyne Alkyne Aldehyde Hydroboration BH3, RBH, THF in H2O2, NaOH =O Oxymercuration Alkene Alkane Reduction Hg(OAc)2, H2O in NaBH4, NaOH Alcohol Alkyne Alkyne Alkene Oxymercuration Hg(OAc)2, H2O in NaBH4, NaOH or HA in H2O Ketone Alkene/yne Alkane H2 or D2 in Lots of H Catalytic Hydrogenation (Lindlar’s) Catalytic Hydrogenation (Wilkinson’s) None Carbocation Stereochem? E2: anticoplanar Rearrange? Yes E1: doesn’t matter H2O, ROH, HX in H2SO4, H2O, HgSO4 Reduction Intermediate Alcohol Alkene Oxidation Mark/Anti Mark addition of halide Carbocation Unknown & Unpredictable Yes Anti-mark addition of alcohol Square concerted transition state Cis products Anti-mark addition of alcohol Square concerted transition state None No No Squiggly line ketone No H & OH on same side (Tautomerizes) Mark addition of alcohol Bridged ion Trans products H2O attacks positive side H & OH on diff side Mark addition of alcohol Bridged ion Trans products Tautomerizes H & OH on diff side None Metal Catalyst Cis products No None Metal Catalyst Cis double bonds No =O= No Ni, Pt, Pd-C Alkene/yne Alkane H2 or D2 in Lots of H Rh(PPh3)3Cl Reaction Partial Catalytic Hydrogenation Reactants Product Mark/Anti Intermediate Stereochem? Rearrange? None Metal Catalyst Cis products No None O-O-CR-O-H Syn No None Ozonide Syn No Syn No Alkyne Alkene H2 in Ni2B(P2), Pd CaCO3 + Pb(OCOCH3)3 + quinoline Lots of H Alkene Epoxide Peroxy Acid (MCPBA, MMPP, RCO3H) O triangle on cyclic Ozonolysis Alkene/yne Ketones (Reductive) O3 in Zn/HOAc, Me2S, DMS DMSO Ozonolysis Alkene/yne Ketones (Oxidative) O3 in H2O, H 2O 2 Carboxylic Acid Strong Oxidative Cleavage Alkene Fragments: ketone, carboxylic acid, & CO2 None None None No Alkyne Oxidative Alkyne Cleavage KMnO4 or O3 1 C: CO2 None None None N/A Dissolving Metal Reduction Alkyne Alkene None None? Trans H products N/A Alkynide Synthesis Alkyne terminal Alkyne nucleophile None None None No (Lindlar’s) Epoxidation KMnO4 or O3 in heat (cyclic) Aldehyde None Ozonide (cyclic) 2+ C chain: Carboxylic acid Li, Na in NH3, other amine Strong base