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Regioselectivity in Tether‐Directed Remote Functionalization – The Addition of a Cyclotriveratrylene‐Based Trimalonate to C 60 Revisited
Author(s) -
Kraszewska Agnieszka,
RiveraFuentes Pablo,
Rapenne Gwénaël,
Crassous Jeanne,
Petrovic Ana G.,
AlonsoGómez José Lorenzo,
Huerta Elisa,
Diederich François,
Thilgen Carlo
Publication year - 2010
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.201000396
Subject(s) - chemistry , regioselectivity , moiety , absolute configuration , enantiomer , stereochemistry , circular dichroism , fullerene , organic chemistry , catalysis
The Bingel addition of a trimalonate derived from a chiral, cyclotriveratrylene (CTV)‐based tripodal tether to C 60 was reinvestigated. The present use of enantiomerically pure ( P )‐ and ( M )‐configured CTV units in the tether allowed the isolation of a total of four enantiomerically pure C 3 ‐symmetric tris‐adducts of [60]fullerene (two from each CTV enantiomer). With the support of NMR and UV/Vis spectroscopy, electronic (ECD) and vibrational (VCD) circular dichroism spectroscopic analysis (comparison to ECD data of known compounds and to ECD and VCD data calculated by TD‐DFT or ZINDO methods as part of this work) allowed a definitive determination of the following structural features for all four CTV‐C 60 conjugates: (i) The constitution of the fullerene addition pattern, (ii) its absolute configuration, and (iii) the absolute configuration of the CTV moiety. It is concluded that the triple Bingel addition proceeded with complete regioselectivity and negligible diastereoselectivity, affording only the trans ‐3, trans ‐3, trans ‐3 fullerene addition pattern in both enantiomeric forms, whereas the previously reported e , e , e motif was not formed.