zed asymmetric SNAr reactions provide unique contribution to the catalyticasymmetric α‐arylations of carbonyl compounds to produce biologically active α‐aryl carbonyl compounds, the electrophiles were limited to arenes bearing strong electron‐withdrawing groups, such as a nitro group. To overcome this limitation, we examined the asymmetric SNAr reactions of α‐amino acid derivatives with arene chromium
尽管相转移催化的不对称S N Ar反应为羰基化合物的催化不对称α-芳基化反应产生了生物活性的α-芳基羰基化合物做出了独特贡献,但亲电试剂仅限于带有强吸电子基团的芳烃,例如硝基。为了克服这一局限性,我们研究了α-氨基酸衍生物与衍生自氟代芳烃的芳烃铬配合物(包括含给电子取代基的芳烃铬配合物)的不对称S N Ar反应。联萘改性的手性相转移催化剂可有效地促进芳基化反应,从而生成相应的α,α-二取代的α-氨基酸,其中包含具有高对映选择性的各种芳族取代基。
Lithiation of 2-, 3-, and 4-fluoroanisole(tricarbonyl)chromium(0) complexes: a reversal of normal regiocontrol
作者:John P. Gilday、David A. Widdowson
DOI:10.1039/c39860001235
日期:——
Lithiation of tricarbonyl(fluoroanisole)chromium(0) complexes occurs exclusively ortho to the fluorine atom, not the oxygen atom as observed in the uncomplexed arenes; the X-ray structure of complex (1) shows that the specificity is not caused by steric inhibition of lithium base co-ordination by oxygen.
GILDAY J. P.; WIDDOWSON D. A., TETRAHEDRON LETT., 27,(1986) N 45, 5525-5528
作者:GILDAY J. P.、 WIDDOWSON D. A.
DOI:——
日期:——
HAMILTON J.; MAHAFFY A. L., SYNTH. AND REACT. INORG. AND METAL-ORG. CHEM., 16,(1986) N 10, 1363-1369
作者:HAMILTON J.、 MAHAFFY A. L.
DOI:——
日期:——
Nucleophilic substitution reactions of (η6-fluorotoluene)Cr(CO)3 and (η6-fluoroanisole)Cr(CO)3 toward phenylacetylide, fluorenyl, indolinyl and carbazolinyl lithium: crystal structures of tricarbonyl[η6-(1,2-diphenylethynyl)benzene]chromium and tricarbonyl[η6-(1,4-fluorenyl)toluene]chromium
作者:Fung-E Hong、Shih-Chun Lo、Ming-Woei Liou、Lung-Fang Chou、Chu-Chieh Lin
DOI:10.1016/0022-328x(96)06131-1
日期:1996.6
(4c) with lithium phenylacetylide (3). The formation of ortho- and meta-products, 7b, 8a and 7a, produced in the above reaction demonstrates that the reaction was by no means through a straightforward nucleophilic substitution mechanism. These results provided support for the mechanism proposed by Pauson and Brookhart, in which the nucleophile attacked the carbon atom of the phenyl ring not bearing
三羰基[ η 6 - (1,2- diphenylethynyl)苯]铬(8A)与三羰基[沿着得到η 6 - (2-苯基乙炔基)茴香醚]铬(7B)和三羰基[ η 6 - (3-苯基乙炔基)茴香醚]铬(7A从三羰基()的反应η 6 -fluoroanisol)铬(4C)与苯基乙炔锂(3)。原产物和元产物7b,8a和7a的形成在上述反应中产生的α,表明该反应决不是通过直接的亲核取代机理进行的。这些结果为Pauson和Brookhart提出的机理提供了支持,其中亲核试剂攻击不带有离去基团的苯环的碳原子,随后氢迁移并最终消除离去基团以获得芳香性。推测是由7b与过量3的反应获得了8a。用质谱,红外,1 H,13 C NMR谱表征化合物。8a的分子结构已通过X射线衍射研究确定。晶体数据如下:斜方晶系,P BCA,。