英语翻译NaH is widely known for its strong basicity and reducing

英语翻译
NaH is widely known for its strong basicity and reducing power,
but not for its alcohols oxidation ability.Intrigued by this
experimental observation,we decided to probe further its capacity
as a useful alcohol oxidant.Although it might be envisioned that
the basic pyridine ring nitrogen atom of the DMAP moiety of 1
might have played a role in promoting the hydride elimination in
the corresponding alkoxide intermediate A,further investigations
on a range of other secondary alcohol substrates quickly revealed
that this was not a structural requisite for its activity,thereby
opening up its wide-ranging substrate scope.
The results are compiled in Scheme 3.Among many secondary
alcohols surveyed under the action of NaH,aryl and heteroaryl
alcohols summarized as structure 3 were found to be substrates of
choice,while alkyl alcohols and propargyl alcohols gave either no
reaction or complicated decomposed mixtures.The oxidation
occurred effectively at room temperature and went to completion
usually within 16-36 h.A solvent screening among THF,DMF,
toluene,and diethyl ether established THF to be optimal.Our
preliminary computational modeling of this novel oxidation process
also suggested that the coordination of THF to the sodium atom
might have played a significant role in lowering the hydride
elimination energy in intermediate A.The isolated yields of ketone
products 4 are generally high,except in the cases of substratesbearing an electron-deficient substituent,in which their correspond-
ing products such as 11 and 15 were obtained in substantially lower
yields.This pronounced electronic effect could reasonably be
attributed to the difficulty of generating ketone carbonyl of high
electrophilic character from a hydride elimination pathway.The
oxidation protocol is exceedingly operationally simple;productions
of 5-8 and 13-14 at 5 g scales,for example,were readily
implementable without compromising the isolated yields and ease
of manipulation,and in all cases the products were easily separated
from the reaction mixture and when desired,prior to aqueous
workup,both NaH and THF could be quantitatively recovered by
filtration of the reaction mixture under a nitrogen atmosphere and
subsequent evaporation of the solvent.6 There is no such issue as
the metal residue or decomposition waste that was incurred by the
oxidant itself.The reaction appeared to be sensitive to the steric
environment of the alkyl-type groups in 3,as replacing the methyl
group in 12-14 with an isopropyl resulted in the loss of reactivity.

氢化众所周知其强碱性,并减少了,但对于本实验观察ability.Intrigued其醇氧化,我们决定共同探讨进一步发挥其作为一个有用的酒精oxidant.Although可能是设想的基本能力,吡啶环氮的1 DMAP的原子基团有可能在促进在相应的醇氢消除中间甲,在其他中学范围进一步调查酒精的作用底物很快发现,这不是它的活动结构的必要条件,从而开放其广泛的底物范围.3.Among在计划下的氢化钠,杂醇芳和行动的许多二级醇调查结果编制的结构3概述被发现物的选择,而烷基醇,丙炔醇可以了没有反应或复杂的氧化分解mixtures.The发生地在室温下完成了在四氢呋喃,二甲基甲酰胺,甲苯和乙醚通常在16-36医管局四氢呋喃溶剂筛选确定初步将optimal.Our这个新的计算模型氧化过程还建议,协调四氢呋喃的钠原子可能起到降低除外substratesbearing一缺电子取代的情况下,在中间答氢消除能源4酮产品的分离率一般都很高,发挥重要作用在他们的对应,荷兰等11个产品,15人取得了明显的大幅下降yields.This电子效应可以合理地归因于生成从氧化氢消除pathway.The议定书高酮羰基亲电性是极为困难业务简单的5-8制作和13-14级在5克例如,很容易被孤立,而又不损害产量可执行和易于操纵,并在所有的产品很容易分离反应混合物,当预期的情况下,前水workup,NaH和四氢呋喃均可以定量收回的反应混合物过滤氮气氛下蒸发和随后的solvent.6没有因为金属的残渣或分解废物是由氧化剂本身发生这样的问题.反应似乎是敏感的烷基- 3型组立体环境,取代了12-14一异丙基甲基组,在反应损失.