Unformatted text preview: 8 -66 u
"": B 03 - THF .. H 20 2 HO - .. 8 -67 By now , these rearrangements should not be so " unexpected" . �H � B n
U" � Cf. H 20 I �C H + H CH3 H a 111 0 CH3
H I I I OH � a lkyl mi gration with ring expansion gives 3° c arbocation in 6-membered ring--carbocation nirvan a ! (Y �
C H3 H
Br : !lr: Y ou must be asking yourself, "Why didn't the methyl group migrate?" To which you answered by drawmg the carbocation that would have been formed: 0
H ' CH] The new carbocation is i ndeed 3 ° , b ut it is only in a 5-membered ri ng, not quite as stable as in a 6 membered ring. In all probability, some of the product from methyl migration would be formed, but the 6membered ring would be the major product. O\}
H � H C H3 I "
H C+ I;I 2° H -- QC<1''3°
H C H3 CH3 8-68 Each alkene w i l l produce two carbonyls upon ozonolysis or permanganate oxidation. Oxidation of the unknown generated four c arbonyls, so the unknown must have had two alkenes . There is only one possibi l i ty for their position s . CO
H KM n04 .. /j. the unknown aCOOH �
187 :: COOH H + C OOH I COOH ...
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This note was uploaded on 02/27/2010 for the course CHEM 140 taught by Professor Wade during the Spring '10 term at Whitman.
- Spring '10