Synthesis of heteroatomic bridged paracyclophanes

• Published in: Dalton transactions : an international journal of inorganic chemistry 2017, Vol.46 (14), p.4530-4541
• Main Authors: Reuter, K, Maas, R G M, Reuter, A, Kilgenstein, F, Asfaha, Y, von Hänisch, C
• Format: Article
• Language: English
• Subjects: Chlorosilanes; Derivatives; Infrared spectroscopy; Isomers; Orientation; Phenyls; Precursors; X ray diffraction
• ISSN: 1477-9226; 1477-9234
• DOI: 10.1039/c7dt00321h

Heteroatomic bridged paracyclophanes were obtained by two independent synthetic approaches. The required precursors consist of para R SiCl (R = Me, iPr) substituted aromatic rings (2 and 4). They were subsequently functionalised by using NH , [LiPH (dme)] or LiAl(PH ) . In the case of the Me-substituted species 2, the reaction with NH directly yielded the Si N bridged paracyclophane 5. The Si P incorporated derivative 10 was obtained by lithiation of p-C H (SiiPr PH ) (9) and subsequent salt metathesis with the chlorosilane 4. The second approach involves the use of GaEt in the formation of four membered (GaPn) cycles (Pn = N, P). p-[C H {SiiPr N(H)GaEt } ] (11) and p-[C H {SiiPr P(H)GaEt } ] (12) represent the first examples of stable (GaPn) cis isomers as the trans species did not appear in solution. Although 11 and 12 show a similar coordination pattern, they differ in the orientation of the aromatic systems: in the solid structure, 11 adopts a - for paracyclophanes so far unique - T-shape conformation of the phenyl rings, while 12 shows the predominant coplanar orientation. All cyclophanes were characterized by X-ray diffraction, elemental analysis, NMR and IR spectroscopy.