10 - Heat evolved upon catalytic hydrogenation (∆ Ho) A...

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Unformatted text preview: Heat evolved upon catalytic hydrogenation (∆ Ho) A MEASURE OF ALKENE STABILITY ALKENE C4H8 H2/Pd-C ALKANE C4H10 EXOTHERMIC ENERGY (-) 28.3 kc al/mol (-) 30.3 kc al/mol (-) 27.4 kcal/mol Best to compare compounds that react to form same alkane Trans > Cis > Geminal 1 SUMMARY OF ALKENE CHEMISTRY (il lustrat ed wi th 1-me thyl cycl opent -1-ene t o emphasiz e transform ation s tereochemi stry) OH HO SYN O O Os H 2O/ H+ mCPBA ANTI H 2O/ H+ SYN OH Br O O HO H Br O sO4 OH O O2 DMS Br2 BH3 H 2/Pd-C SYN SYN SYN O H ANTI O BH2 H H Br Br Br H 2O2 NaO H H SYN OH H POLYOL NATURAL PRODUCTS O OH OH OH HO OH OH O OH O O HO O O HO O OH n CELLULOSE O OH ERYTHRONOLIDE A (ERYTHROMYCIN A) Antibiotic OH OH O HO OH O OH OH OH OH O O AMPHOTERICIN B Antifungal CO2 H O NH2 OH Me OH 2 NATURAL PRODUCTS WITH ALKENE FUNCTIONALITY b -Pi nen e g- Bisabo l en e A sesqu iterp ene fou nd in th e essenti al o il s o f a nu mb er of p lan ts L imo nen e A mo n oterp ene com mon i n citru s fru its Cem brene A d i terp en e from p in e n eed les O Caryo p hyll ene A co nsti tuen t of clo ve oi l Carvon e Sp earmin t o il b -Caroten e (A vitami n) A t et rat erp ene brig h t o ran g e in col or and th e p recu rsor to the visu al pi gmen t reti nal OH Vi tamin A (visi on ) MARKOVNIKOV and ANTI-MARKOVNIKOV ADDITION TO ALKENES R-O-O -R R-O + H Br 2 R -O R-O H + B r H+ Br Br - Markovnikov Br I n the dark , in the abs enc e of pe rox ides polar so lven ts to pr omote fo rma tio n of po lar inte rme diate . M os t s ubs tituted ca rbo nium ion inte rme diate gi ves mos t s ubs ti tute d brom ide pr oduc t Br H Br AntiMarkovnikov Br I n the p re se nce o f pe ro xide s and he at o r light to pro mote homo lytic c lea vage of O-O bond. M os t s ubs titute d ra dical inter me diate giv es leas t s ubstitute d b rom ide pro duct 3 ALKENE POLYMERIZATION - SPECIAL TOPIC STRUCTURE POLYMER (trade name) ethene H 2 C CH2 pol yethylene ( pol ythene) propene H 2 C CH CH3 polypropyle ne MONOMER chloroet hene (vi nyl chlori de) PVC ( polyvinyl chloride) H2 C CH Cl acryloni tril e H H2 C C tet rafl uor oethene F2C O rlon (ac rilan) CN CF 2 TEFLO N H H2 C C phenylet hene (s tyrene) PO LYSTYRENE met hylmet hacrylate LUCITE (Pl exiglas s) OMe O 1,1-di chloroethene and 1-chloroe thene Random co- polymer SARAN WRAP H2 C CCl2 H2 C CHCl F R E E R A D I C A L P O L Y ME R I Z A T I O N INI TIATION, PROPAGATI ON (POLYMERI ZATION) and TERMINATION STEPS IN ITI AT IO N O 2 O O 2 O OO + 2 C O2 POL YM ER IZA TI ON TER MI NA TIO N n Ph n Ph 4 F R E E R A D I C A L P O L Y ME R I Z A T I O N INI TIATION, PROPAGATI ON (POLYMERI ZATION) and TERMINATION STEPS IN ITI AT IO N O 2 O O 2 O OO + 2 C O2 POL YM ER IZA TI ON TER MI NA TIO N n Ph n Ph CATIONIC POLYMERIZATION INITIA TION, PR OPAG ATION (PO LY MER IZATION ) a nd TERMI NA TIO N STEPS IN ITI AT IO N G ood monomer f or cationi c pol ymeri zation..Why? H+Cl- What about te trafl uoroethene? P O L Y ME R I Z A T I O N TER MI NA TIO N - H+ n 5 CHOLESTEROL BIOSYNTHESIS Sq ualene epo xid ase [O2] Sq ualene O O Oxid osqu alene cyclase Me Me Me HO Me + Me H Me + Me Me H H HO HO H+ H Me Me 5 H H 6 H C HO LESTER OL O Oxid osqu alene cyclase Me Me Me HO Me Me 6 ...
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This note was uploaded on 11/27/2011 for the course CHEMICAL E 20.410j taught by Professor Rogerd.kamm during the Spring '03 term at MIT.

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