Organic Chemistry Reactions----------------------------------------1. Alkene halogenation  more stable carbocation (1,2-methyl/hydride shift)  most-substituted carbon addition2. Alkene hydration  conversion to an alcohol via acid-catalytic addition on most-substituted carbon 3. Alkoxylation of an alkene by addition of a nucleophile (like methanol) other than water or a halogen  ether product on most stable carbocation by subsequent deprotonation 4. Dihalogenation of cyclic alkene  halonium ion leading to attack from above/below, resultingin trans-configuration addition in a diastereospecific but racemic manner5. Hypohalous acid addition to alkenes  halogen on least-substituted carbon (with positive charge) and diol added to the most substituted (most stable) carbocation 6. Alkene hydroboration  alkylborane on the least-substituted carbon due to steric hindrance; reaction with hydroxide and peroxide forms an alcohol by replacement (BH2  OH) rationalized by the complex transition state without an intermediate; ether solventa. Dislamylborane and 9-BBN are more selective borane units, providing greater selectivity due to increased steric hindrance by mass (regioselectivity); OH replacement7. Oxymercuration of an alkene  addition of HgOAc (mercury) on least-substituted carbon (most-stable carbocation)  OH addition by reaction with NaBH4 removal of Hg (back-donation by the d-orbital)a. Alkoxymercuration uses an alcohol solvent rather than water, leading to an ether, from EtOH to OEt by subsequent deprotonation 8. Permanganate hydroxylation of alkenes  concerted 1,3-dipolar cycloaddition forming a manganate ester (five-membered ring) that leads to a cis-diol with addition of water and OH9. Osmylation hydroxylation of alkenes  formation of an osmate ester ring by OsO4 leads to a cis-diol in a diastereospecific racemic mix; catalytic NMO regenerates OsO410. Epoxidation of alkenes  reaction with peroxyacid (CH3CO3H) yields oxirane and carboxylicacid in a diastereospecific racemic mixture by a complex transition state; cis-configuration11. Ozonolysis of alkenes  forms an ozonide rearrangement after 1,3-dipolar cycloaddition yields an initial 1,2,3-trioxolane; addition of H2O2 gives a ketone and carboxylic acid, while addition of H3CSCH3 (sulfur derivative) gives a ketone and aldehyde (2 products for both)12. Alkyne halogenation  more stable carbocation (no rearrangement due to pi-bond)  most-substituted carbon addition of the halogen with retention of the double-bond (E+Z four products)13. Alkyne hydration  acid-catalyzed nucleophilic addition of water to the most-stable carbocation  deprotonation leads to an enol that undergoes keto-enol tautomerization14. Oxymercuration of an alkyne  mercury is lost when the enol is formed, leading to keto-enol tautomerization to give a ketone product; NABH4 is not needed in this reaction, just strong acid, like H2SO415. Alkyne hydroboration  less-sterically hindered product on the less substituted carbon without a carbocation, leading to replacement of boron with OH giving an enol, which tautomerizes to the terminal aldehyde16. Dihalogenation of alkynes  trans configuration addition of two halogens with retention of double bond 17. Radical formation  azo compound reagent generates radicals; alkenes and HBr with additionof UV light or peroxides give a bromide addition on the least substituted carbon (anti-Markovnikov addition) 18. Sn2 reaction  2nd order collision without intermediates and with 100% inversion; tertiary halides do not react due to higher energy transition state from steric hindrance; rate depends on concentration of nucleophile; has aprotic solvents like THF to prevent solvation interferencea. Halide nucleophile  good leaving groups due to electronegative stabilization; same goes for sulfonate esters (like benzene sulfonyl) due to resonance-stabilization; proceeds in backside attack (Walden inversion) from the pentacoordinate transition stateb. Alkoxide nucleophile  product of an alcohol and base; reacts with primary and secondary halides to form a Williamson ether synthesisc. Amine nucleophile  nitrogen displaces the alkyl halide to form an ammonium-salt in an acid-base reaction; secondary amines are more nucleophilic than primary amines, while exhaustive methylation leads to multiple productsd. Phthalimide amine surrogate  reaction with sodium amide leads to an amine (good nucleophile with alkyl halides) and phthalic acide. Azide amine surrogate  azide ion (N3) and alkyl halide forms an azide (alkyl N3) by an Sn2 reaction  treatment with NaBH4 yields an amine (alkyl NH2)f. Cyanide amine surrogate  bidentate nucleophile (carbon is more nucleophilic if K or Na are used; nitrogen is more nucleophilic if others are used, forming isonitriles) reacts with alkyl halides to form a nitrile (alkyl CN) replacing the halogeng. Phosphine and an alkyl halide  substitution of the halogen by phosphine forms a phosphonium salt (similar to amines forming an ammonium salt) that is more stable than an ammonium salt due to the lack of exhaustive methylation19. Sn1 reaction  1st order ionization using elimination of chirality due to planar carbocation intermediate with no facial selectivity; uses water or aqueous solution for solvation; primary halides do not undergo Sn1 reactions due to high transition state/less carbocation stability; rate of reaction does not depend on nucleophile concentration and alkyl/hydride rearrangement can happena. Hydration substitution of an alkyl halide  halogen is replaced by an oxonium ion through oxygen nucleophile of H2O, which undergoes deprotonation to alcohol