Enantiomerically Pure Cyclic trans-1,2-Diols,Diamines, and Amino Alcohols by Intramolecular Pinacol Coupling of Planar Chiral Mono-Cr(CO)3 Complexes of Biaryls |
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Authors: | Nobukazu Taniguchi Takeshi Hata Motokazu Uemura |
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Abstract: | Without any formation of stereoisomers , the intramolecular pinacol cyclization of 1 —planar chiral mono-Cr(CO)3 complexes of 1,1′-biphenyls with carbonyl functionalities at the 2- and 2′-positions—with samarium diiodide gives cyclic trans-1,2-diols 2 . Upon exposure to sunlight, the chromium-complexed diols 2 produce optically pure chromium-free trans-diols 3 . Similarly, the corresponding enantiomerically pure trans-1,2-diamines and amino alcohols are obtained from the planar chiral chromium complexes of biphenyls with diimino or keto-imino functionalities. R1=H, OMe; R2=H, Me; R3=H, Me. |
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Keywords: | Arene complexes Chirality Chromium Pinacol coupling Samarium |
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