TY  - JOUR
A1  - Storch, Golo
A1  - Maier, Frank
A1  - Wessig, Pablo
A1  - Trapp, Oliver
T1  - Rotational Barriers of Substituted BIPHEP Ligands: A Comparative Experimental and Theoretical Study
JF  - European journal of organic chemistry
N2  - The interconversion barriers of 14 different 3,3- and 5,5-disubstituted tropos BIPHEP [2,2-bis(diphenylphosphino)-1,1-biphenyl] and BIPHEP(O) [2,2-bis(diphenylphosphoryl)-1,1-biphenyl] ligands were investigated by enantioselective dynamic high performance liquid chromatography (DHPLC) and DFT calculations using the B3LYP/6-31G* and M06-2X/6-31G* levels of theory. The experimentally determined enantiomerization barriers varied from 86.8 to 101.4 kJmol(-1) and were found to be in excellent agreement with the calculated data. The root-mean-square deviations are 7.3 kJmol(-1) for the B3LYP functional and 11.3 kJmol(-1) for the M06-2X method.
KW  - Rotational barriers
KW  - Density functional calculations
KW  - Enantioselectivity
KW  - P ligands
KW  - Biaryls
KW  - Liquid chromatography
Y1  - 2016
U6  - https://doi.org/10.1002/ejoc.201600836
SN  - 1434-193X
SN  - 1099-0690
VL  - 22
SP  - 5123
EP  - 5126
PB  - Wiley-VCH
CY  - Weinheim
ER  - 
TY  - JOUR
A1  - Wessig, Pablo
A1  - Matthes, Annika
A1  - Schilde, Uwe
A1  - Kelling, Alexandra
T1  - Asymmetric synthesis of (1,5)Naphthalenophanes by Dehydro-Diels-Alder reaction
JF  - European journal of organic chemistry
N2  - An asymmetric variant of the dehydro-Diels-Alder (DDA) reaction has been developed and applied in the atropselective synthesis of various (1,5)naphthalenophanes. Whereas the suitability of the photochemically induced DDA (PDDA) was limited, the thermally induced DDA provided the desired product, depending on the chiral auxiliary used and the length of the linker, with nearly perfect stereoselectivity. Furthermore, the mechanism of the DDA was investigated by means of DFT calculations, and a stepwise mechanism involving 1,4-biradicals was suggested.
KW  - Synthetic methods
KW  - Macrocycles
KW  - Cyclophanes
KW  - Atropisomerism
KW  - Chiral auxiliaries
KW  - Density functional calculations
Y1  - 2013
U6  - https://doi.org/10.1002/ejoc.201201594
SN  - 1434-193X
IS  - 11
SP  - 2123
EP  - 2129
PB  - Wiley-VCH
CY  - Weinheim
ER  -