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|Title:||Oxygen-initiated stereoselective thermal isomerisation of a cyclobutane derivative in the solid state||Authors:||Chanthapally, Anjana
Quah, Hong Sheng
Webster, Richard D.
Schreyer, Martin K.
Wong, Ming Wah
Vittal, Jagadese J.
|Keywords:||DRNTU::Science::Chemistry::Organic chemistry::Oxidation||Issue Date:||2014||Source:||Chanthapally, A., Yang, H., Quah, H. S., Webster, R. D., Schreyer, M. K., Wong, M. W., et al. (2014). Oxygen-initiated stereoselective thermal isomerisation of a cyclobutane derivative in the solid state. Chemistry - a European journal, 20(48), 15702-15708.||Series/Report no.:||Chemistry - a European journal||Abstract:||Solid-state [2+2] photochemical cycloaddition reactions have been extensively studied after the classical work of Schmidt in the 1960s. Of these, trans-1,2-bis(4′-pyridyl)ethylene (bpe) is one of the well-studied alkenes to synthesize tetrakis(4-pyridyl)cyclobutane (tpcb). However, almost all the solid-state [2+2] cycloaddition reactions of bpe yielded, almost exclusively, one of the four possible isomers, namely, the rctt-tpcb (r=regio c=cis and t=trans). Here we describe a stereoselective synthesis of the tetrahedrally disposed rtct-tpcb by the solid-state thermal isomerization of the rctt-isomer in atmospheric air. We propose that this isomerization occurs through a topochemical unimolecular mechanism by a radical chain pathway, initiated by molecular oxygen. This is supported by the nature of products formed in air and nitrogen, detection of a radical in ESR spectral studies, ESI-MS crossover experiments, VT PXRD studies along with QM, MD and docking calculations. The formation of a unique isomer by thermal isomerization may be a general phenomenon to quantitatively synthesize other useful stereoisomers from the existing isomers of cyclobutane derivatives.||URI:||https://hdl.handle.net/10356/107432
|ISSN:||0947-6539||DOI:||10.1002/chem.201405228||Rights:||© 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.||Fulltext Permission:||none||Fulltext Availability:||No Fulltext|
|Appears in Collections:||SPMS Journal Articles|
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