Catalytic access to ferrocenyl phosphines bearing both planar and central chirality – A kinetic resolution approach via catalytic asymmetric P(III)–C bond formation
作者:Abdul Sadeer、Tadayuki Kojima、Jia Sheng Ng、Kennard Gan、Renta Jonathan Chew、Yongxin Li、Sumod A. Pullarkat
DOI:10.1016/j.tet.2020.131259
日期:2020.6
A series of enantioenriched ferrocenyl monophosphines imbued with both central and planarchirality were obtained catalytically (80–99% ee) via the kinetic resolution of 1,2-disubstituted planarchiral ferrocenyl enone racemates. The synthetic approach utilized a chiral palladacycle to facilitate the asymmetric hydrophosphination (AHP) as a means to achieve high stereoselectivity. The enantioenriched
Acetylides of cycloplatinated ferrocenylamines; synthesis and redox chemistry†
作者:C. John McAdam、Evan J. Blackie、Joy L. Morgan、Sarah A. Mole、Brian H. Robinson、Jim Simpson
DOI:10.1039/b101776o
日期:——
Sonogashira coupling of a terminal alkyne with cycloplatinated ferrocenylamine complexes gave the acetylides Pt[RCC][Me2NCH2(σ-Fc)]dmso}, which were characterised by analysis, spectroscopy and, for the R = SiMe33, Fc 5 complexes, X-ray structural analyses. A butadiyne complex was also isolated in reactions of 3. Equivalent reactions with LDA led to an unusual deplatination reaction to give the ethynylferrocenylamine. The Pt(II) centre functions as a redox switch at E+/0 = ∼0.21 V and the spectroscopic and electrochemical data show that the acetylide is a π-donor ligand. There is a strict delineation of the electronic requirements for the trans Pt–N and trans Pt–C(Cp) groups in these cycloplatinated compounds. Oxidation of 3 gives rise to low energy bands based on the Pt(II) unit; an additional broad band at 1100 nm occurs in 5+ but not 52+.
Kinetic resolution of racemic planar-chiral metallocenes was performed by a resin-supported peptide catalyst, in which low-molecular-weight organocatalysts were not effective.
Palladium-catalyzed reaction of 2-iodoferrocenyl alcohols with internal alkynes: Synthesis of functionally 1,2-disubstituted ferrocenes and ferroceno-pyrans
The reaction of racemic (2-iodoferrocenyl)methanol with internal alkynes in the presence of (dppf)PdCl2 and i-Pr2NH produces alkenyl-substituted ferrocene carboxaldehydes in moderate yields. All reactions are carried out at 100 or 120 °C for different reaction times (between 6 and 26 h) in a screw-cap Pyrex bottle. The scope and limitations of this reaction are studied by employing variously substituted
elaborated to convert [(dimethylamino)methyl]ferrocene into racemic mixtures of the first representatives of planar‐chiral 4H‐ferroceno[e][1,3]thiazines. A similar strategy with 2‐iodobenzyl bromide as the precursor enabled a highly improved synthesis of 2‐ferrocenyl‐4H‐benzo[e][1,3]thiazine. The relative tendency of the new ferrocene‐based thiazines, composed of potential redox sites assembled in different
2-二茂铁基-4- H-苯并[ e ] [1,3]噻嗪及其6,7-二甲氧基衍生物是通过二茂铁羧酰胺,甲醛和相应的苯硫酚的曼尼希加合物的Bischler-Napieralski型环化法制备的。精心设计了一条更有效的合成途径,包括定向的锂化/碘化序列,然后进行标准的官能团转化和最终的铜催化的环化反应,将[(二甲基氨基)甲基]二茂铁转化为平面手性的首批代表的外消旋混合物。 4 H-二茂铁[ e ] [1,3]噻嗪。以2-碘苄基溴为前体的类似策略可大大改善2-二茂铁基-4 H-苯并[ e]的合成] [1,3]噻嗪。通过循环伏安法(CV)和DFT计算研究了由以不同分子结构组装的潜在氧化还原位点组成的新型二茂铁基噻嗪在单电子转移(SET)反应中作为供体的相对趋势。结果表明2-二茂铁基-4- H-二茂铁[ e ] [1,3]噻嗪可以经历两个连续的氧化还原步骤,并且是制备模型中最有效的还原剂。它具有最低的