Structure and dynamic features of an intramolecular frustrated Lewis pair.
Di(mesityl)cyclohexenylphosphine undergoes hydroboration with Piers' borane [HB(C(6)F(5))(2)] to yield the cyclohexylene-anellated frustrated Lewis pair 5. This P/B pair splits H(2) with the formation of the product 4 and adds to the C=O double bond of phenyl isocyanate to yield 6. In the crystal, compound 5 features a puckered four-membered heterocyclic core structure with a long P-B bond (av. 2.197(5) Å). The activation energy of the P-B cleavage of the frustrated Lewis pair 5 was determined by dynamic (19)F NMR spectroscopy at ΔG(≠)(298 K)=12.1±0.3 kcal mol(-1).
Axenov
Kirill V
KV
Organisch-Chemisches Institut der Universität Münster, Corrensstrasse 40, 48149 Münster, Germany.
Mömming
Cornelia M
CM
Kehr
Gerald
G
Fröhlich
Roland
R
Erker
Gerhard
G