2593-53-5Relevant articles and documents
Symmetry in Cascade Chirality-Transfer Processes: A Catalytic Atroposelective Direct Arylation Approach to BINOL Derivatives
Wang, Jin-Zheng,Zhou, Jin,Xu, Chang,Sun, Hongbin,Kürti, László,Xu, Qing-Long
, p. 5202 - 5205 (2016)
Herein we disclose a scalable organocatalytic direct arylation approach for the regio- and atroposelective synthesis of non-C2-symmetric 2,2′-dihydroxy-1,1′-binaphthalenes (BINOLs). In the presence of catalytic amounts of axially chiral phosphoric acids, phenols and naphthols are coupled with iminoquinones via a cascade process that involves sequential aminal formation, sigmatropic rearrangement, and rearomatization to afford enantiomerically enriched BINOL derivatives in good to excellent yields. Our studies suggest that the (local) symmetry of the initially formed aminal intermediate has a dramatic impact on the level of enantioinduction in the final product. Aminals with a plane of symmetry give rise to BINOL derivatives with significantly lower enantiomeric excess than unsymmetrical ones featuring a stereogenic center. Presumably asymmetric induction in the sigmatropic rearrangement step is significantly more challenging than during aminal formation. Sigmatropic rearrangement of the enantiomerically enriched aminal and subsequent rearomatization transfers the central chirality into axial chirality with high fidelity.
Synthesis and antidepressant evaluation of three para-benzoquinone mono-oximes and their oxy derivatives
De Sousa, Damiao Pergentino,Schefer, Renata Rabelo,Brocksom, Ursula,Brocksom, Timothy John
, p. 148 - 155 (2007/10/03)
A series of three para-benzoquinone mono-oximes and four oxy-derivatives were prepared and tested for their antidepressant properties. The (4E) oxime of 2-isopropyl-5-methyl-para-benzoquinone (4) and the corresponding 2-diethylamino-ethyl derivative (10)
