A Widely Applicable Method of Resolution of Binaphthyls: Preparation of Enantiomerically Pure 1,1'- Bin aphthalene-2,2'-diol, 1,1'-Binaphthalene-2,2'-dithiol, 2'-Mercapto-1,1 '-binaphthalen-2-ol, and 1,1'-Binaphthalene-8,8'-diol

摘要

"Man-made" chiral auxiliaries are becoming increasingly popular over the classic auxiliaries derived from the natural chiral pool. From a practical point of view, a requisite that should be fulfilled to make a "man-made" auxiliary directly comparableto a "natural" one is that the ease of resolution matches the ease of extraction and of the further manipulations that are ordinarly required to a natural compound to make it suitable for asymmetric synthesis. When this is accomplished, one can make useof reagents to meet all needs and to incorporate a number of features that are otherwise not possible with natural substances. Among the many virtues of man-made auxiliaries we can cite the high-symmetry chirality, the high crystallinity, the simple spectra, the accessibility to both enantiomers, and the virtual accessibility to any functional group. Among the most well-known examples of man-made auxiliaries are 1,1'-binaphthalene-2,2'-diol (la) and -dithiol (2H).