Remarkably Slow Rotation about a Single Bond between an sp<sup>3</sup>-Hybridised Carbon Atom and an Aromatic Ring without<i>ortho</i>Substituents
作者:Sarah Murrison、David Glowacki、Christian Einzinger、James Titchmarsh、Stephen Bartlett、Ben McKeever-Abbas、Stuart Warriner、Adam Nelson
DOI:10.1002/chem.200802127
日期:2009.2.16
ortho substituents! A series of polycycles were prepared by using a three‐component Joullié–Ugi reaction. The rate of rotationabout the bond between a highly hindered bridgehead and a phenyl ring with no ortho substituents was measured, and was highly dependent on the substitution. Rotamer half‐lives of up to 21 h at 298 K were observed (see figure). Rotamers resulting from this restricted rotation
[reaction: see text] Palladium-catalyzedcross-coupling of vinyl- and arylstannanes with pi-electron-deficient heteroaromatics was performed in good yields. This Stille-type reaction was carried out with a methylthioether function as an electrophile in the presence of a copper(I) bromide-dimethyl sulfide complex.