Reported is a single high yielding step approximation to mixed olefin/sulfinamide ligands enclosing a chiral sulfur atom as the sole chiral center. The synthetic design is validated by a rapid optimization of the substituent at the sulfinyl sulfur, and by the synthesis of an efficient, highly enantioselective catalyst for the Rh-catalyzed 1,4-addition of boronic acids to both, cyclic and acyclic olefins
Axial Chirality Control During Suzuki−Miyaura Cross-Coupling Reactions: The <i>tert</i>-Butylsulfinyl Group as an Efficient Chiral Auxiliary
作者:Françoise Colobert、Victoria Valdivia、Sabine Choppin、Frédéric R. Leroux、Inmaculada Fernández、Eleuterio Álvarez、Noureddine Khiar
DOI:10.1021/ol9020755
日期:2009.11.19
An efficient route to a new family of axially chiral biaryl ligands by a Suzuki−Miyaura cross-coupling reaction between ortho,ortho′-disubstituted aryl iodides bearing in ortho position a tert-butyl or p-tolylsulfinyl group and ortho-substituted phenyl boronic acids or esters is described. The comparison between the t-BuSO and p-TolSO groups as chiral controllers is reported. The modularity of the
Mid-infrared vibrational unpolarised absorption and vibrational circulardichroism (VCD) spectra of CCl4 solutions of tert-butyl methyl sulfoxide (1) are reported. The spectra are compared to ab initio density functional theory (DFT) calculations carried out using two functionals, B3PW91 and B3LYP, and two basis sets, 6-31G* and TZ2P. The VCD spectra are calculated using Gauge-invariant atomic orbitals
A convergent enantioselective synthesis of (+)-royleanone (1) is described starting from enantiomerically pure (S)-3-hydroxy-2-isopropyl-5-tert-butylsulfinyl-p-benzoquinone, which is readily available from 3-isopropyl-1,2,4-trimethoxybenzene and 1,3,3-trimethyl-2-vinylcyclohexene. The key step is a tandem asymmetric Diels-Alderreaction/pyrolytic sulfoxide elimination process.