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Efficient Synthesis of a Chiral [4]Pseudocatenane and Its Derivatives: A Novel Ship's Wheel‐like Interlocked Structure
Author(s) -
Zhu XiaoZhang,
Chen ChuanFeng
Publication year - 2006
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.200600195
Subject(s) - chemistry , molecule , stereocenter , chirality (physics) , acetonitrile , chromophore , stereochemistry , medicinal chemistry , organic chemistry , catalysis , enantioselective synthesis , chiral symmetry breaking , physics , quantum mechanics , quark , nambu–jona lasinio model
A novel chiral[4]pseudocatenane 5 H 3 [PF 6 ] 3 was synthesized efficiently by treatment of a solution of chiral triptycene‐based tri(crown ether) 1 and three equivalents of a bis[ p ‐(but‐3‐enyloxy)benzyl]ammonium salt in CH 2 Cl 2 with a Grubbs II catalyst, followed by hydrogenation. It was found that the ammonium groups in 5 H 3 [PF 6 ] 3 could be deprotonated by 1,8‐diazabicyclo[5.4.0]undec‐7‐ene (DBU) in acetonitrile or dimethyl sulfoxide (DMSO). Consequently, N‐acylation of the ammonium groups was easily performed in the presence of DBU, which resulted in a new class of neutral highly ordered interlocked molecules in good yields. In particular, the incorporation of stopper units, for example, diethyl phosphoramidate, lead to the isolation of the interlocked molecule 10 with an interesting ship's wheel‐like structure, which was structurally studied with the help of detailed NMR experiments. Compared with 1 , it was further found that the Cotton effect of ( R )‐1,1′‐binaphthyl chromophore at 241 nm was greatly reduced in 5 H 3 [PF 6 ] 3 and its derivatives. Moreover, a new positive Cotton effect at 248 nm appeared in the interlocked molecules; this observation could be attributed to the chirality transfer from the binaphthyl units to the macrocycles lying in the cavities of 1 .