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Synthesis of Polyether Cyclophanes through Rhodium‐Catalyzed Cross‐Alkyne Cyclotrimerization
Author(s) -
Tanaka Ken,
Sagae Hiromi,
Toyoda Kazuki,
Noguchi Keiichi
Publication year - 2006
Publication title -
european journal of organic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.825
H-Index - 155
eISSN - 1099-0690
pISSN - 1434-193X
DOI - 10.1002/ejoc.200600232
Subject(s) - chemistry , rhodium , alkyne , cationic polymerization , dimethyl acetylenedicarboxylate , cyclophane , yield (engineering) , catalysis , ether , polymer chemistry , medicinal chemistry , crystal structure , stereochemistry , organic chemistry , cycloaddition , materials science , metallurgy
Cross‐cyclotrimerizations of ether‐linked α,ω‐diynes and dimethyl acetylenedicarboxylate in the presence of a catalytic amount of cationic rhodium(I)/H 8 ‐BINAP complex give [7]–[21]polyether cyclophanes in good yield. [8]–[9]Ester cyclophanes were also synthesized from the corresponding α,ω‐diynes. The ratio of para‐, meta‐, and orthocyclophanes depends on the length and the structure of the α,ω‐diyne tether chain, whilst the effect of concentration on the yield of polyether cyclophanes appears to be small. X‐ray analysis revealed that a single crystal of [15]metacyclophane 4g was the chiral form and that of [5.5]metacyclophane 4k the racemic form, due to an absence of ring flip in the crystals. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006)