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Unformatted text preview: Catalyzed Ionic Additions BaseC atalyze Me d chanism s: XY = HNu Acid C atalyze Me d chanism s: XY = HNu 1. Hydration: Geminal Diols
(Carbonyl Hydrates) K ~1 K de nds on "unhappine of C=O polarization: pe ss" Ele ctron-withdrawing substitue activate donors nts , de activate . Me chanism s: H = -5.30 kcal m -1, S = -17.2 e G = ol u, -0.18 kcal m -1 ol H = -3.09 kcal m -1, S = -22.9 e G = ol u, +3.74 kcal m -1 ol 2. Addition of Alcohols
S eas wate initially, to formhe iace am r, m tals K
H or HO K varie from< 1 s to > 1, as with wate De nds on r. pe R. K
H or HO (Not he ike m tal: I UPAC ) I ntram cular variant (important for sugars, Chapter ole
24): Best for 5- and
6-m m re rings. e be d K >1! Favore by e d ntropy re lativeto inte...
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- Spring '09