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Unformatted text preview: 4 -46 continued ( d) (e) �
decalin - CO
CHCH3 I I U
h Br 3' hydrogen abstracted selectively. faster than 2' (f)� �
Br Br + 3 ° hydrogen abstracted selectively , faster than 2° or 1 ° � Br both 2°-formed in equal amounts from resonance-stabi l i zed benzylic radical ( h) 4-47 (a) As i s produced, it c an c ompete with generate CHCI3, etc. RroRagation steRs +
• Q¢-OQ+ cb
Br A l l hydrogens at the starred positions are equi valent and allylic. T he from the lower ri ght carbon has been removed to make an intermedi ate w i th two non-equivalent resonance forms, giving the two products shown . Drawing the resonance fonns is the
key to answering this question correctly. H ( b) To maxi mize H l and minimize formation of polychloromethanes, the ratio of methane to chlorine must be kept high (see problem 4-2). To guarantee that all hydrogens are replaced with chlorine to produce CCI4, the ratio of chlorine to methane must be kept high. CCH3 CC·l2 H4 CCCH2C\ CCl2 3 CH2Cl2 CCl· CHCl33 Cl2l2 C Cl C 3C
l lH + l
• • • C HCl2 + Cl + • + + + + • ..... .. .. ... HCl ClCH3 HCl CCl HH2C\2 CHCl3 HC CCl4
l+ +++ CCCH3·2C C· + +CCHCl2 C· +·
• • CH4 f or avai l able Cl ., generatin g CH2Cl2. This can l H l l • + • l C l3 Cl 73 ...
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