作者volley (生涯第一支全垒打)
看板Chemistry
标题Re: 一题有机...
时间Fri Feb 17 22:27:42 2006
Negative, the sp2 carbon (ipso carbon of phenyl triflate) would not
react with amide ion via either Sn1 or Sn2 mechanism.
the high reactivity of benzylic position toward substitution reaction
is attributed to the stability of reaction intermediate. This reason
can not stand well in this case.
But it does not mean that this reaction will not go.
A point that I must emphasize here is "the reaction mechanism".
Phenyl triflate, in which a good leaving group is contained, "might"
react with strong nucleophile under strong conditions. It undergoes
SnAr mechanism. But in fact, this reaction occurs via benzyne mechanism
instead of SnAr because that SnAr takes place while strong electron-
withdrawing groups are contained in phenyl trilate. The simple
"unactivated" phenyl trilate shows very poor activity toward SnAr.
On the other hand, benzyne mechanism is a possible pathway to transfer
phenyl triflate to aniline.
The difficulty of the use of NaNH2 is the major problem to utilize
this reaction to transfer phenyl triflate to aniline. Thus, the
alternative "transition-metal-catalyzed" amination is wildly adopted
to do amination. For example, Buchwald-Hartwig amination transfers
aromatic halide or aromatic triflate to N-substituted aniline in the
presence of palladium catalyst with moderate to high yield and
relatively mild reaction conditions.
※ 引述《CsmuKoji (hiphop MUSIC  )》之铭言:
: 可以从phenyl triflate然後加 NaNH2
: 走benzylic的反应机构 然後得 aniline吗
: 不好意思 突然想到的 ^^"
: ※ 引述《volley (生涯第一支全垒打)》之铭言:
: : 我猜...先做成phenyl triflate,再用钯催化进行Hartwig amination,
: : 得到N-ethylaniline,以过量碘甲烷与之反应得到ammonium salt後
: : 进行Hoffmann elimination即可...
: : 真麻烦.
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A:一颗快速直球...让你投得既不快速又没有尾劲,失败...
滑球一出手,没弧度...失败.. 曲球不会弯曲..失败...
指叉球又掉不下来,一投就被打全垒打~失败中的失败
最惨的就是打者了,根本打不到球,还被触身!!你有没有搞错!!!!!
喂!!触身咧...喂!!触身打到我了你有没有看到!!!!!
B:叫防护员上来冰敷吧!
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※ 发信站: 批踢踢实业坊(ptt.cc)
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1F:推 CsmuKoji:谢谢唷 学到了更多 02/17 23:56
2F:推 CsmuKoji:所以用金属的话 还是比较好了 金属还真奇妙 02/17 23:59