Copy of Chapter 17

E be d k 1 favore by e d ntropy re lativeto inte ole

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Unformatted text preview: ole rm cular addition: G = H - TS S is le ne ss gativefor intram cular ole re action. Wecan drivethehe iace ste furthe with m alcohol and m tal p r ore with H (not HO-) catalysis: Ace tals K >1! (isolated) (A ge inal die r) m the Ace arestableto: tals Oxidizing age nts Nucle ophile (Grignards, s alkyllithium hydride s, s) tals Base Ace areNOT stable to: Acid (you can re rsetheabovewith ve e ss H2O) xce Me chanism : Addition of R'OH to carbonyl function Re place e of HO- with R'Om nt Ace tal I ntram cular variant (important for sugars, Chapter ole 24). Best for 5- and 6-membered rings. o O HO H C 3OH, H+ H o Cyclic Acetals: Protecting Groups H,HO Hydrolysis = Deprotection O 1. HO OH O 2. Mg O 3. Br H OH 4. H+, H2O This is also a m thod to pro...
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