Synthesis and Catalytic Application of Chiral 1,1'-Bi-2-naphthol- and Biphenanthrol-Based Pincer Complexes: Selective Allylation of Sulfonimines with Allyl Stannane and Allyl Trifluoroborate

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• 作者：Juhanes Aydin ; K. Senthil Kumar ; Mahmoud J. Sayah ; Olov A. Wallner ; K&aacute ; lm&aacute ; n J. Szabó
• 刊名：Journal of Organic Chemistry
• 出版年：2007
• 出版时间：June 22, 2007
• 年：2007
• 卷：72
• 期：13
• 页码：4689 - 4697
• 全文大小：241K
• 年卷期：v.72,no.13(June 22, 2007)
• ISSN：1520-6904

文摘

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New easily accessible 1,1'-bi-2-naphthol- (BINOL-) and biphenanthrol-based chiral pincer complexcatalysts were prepared for selective (up to 85% enantiomeric excess) allylation of sulfonimines. Thechiral pincer complexes were prepared by a flexible modular approach allowing an efficient tuning ofthe selectivity of the catalysts. By employment of the different enantiomeric forms of the catalysts, bothenantiomers of the homoallylic amines could be selectively obtained. Both allyl stannanes and allyltrifluoroborates can be employed as allyl sources in the reactions. The biphenanthrol-based complexesgave higher selectivity than the substituted BINOL-based analogues, probably because of the well-shapedchiral pocket generated by employment of the biphenanthrol complexes. The enantioselective allylationof sulfonimines presented in this study has important implications for the mechanism given for the pincercomplex-catalyzed allylation reactions, confirming that this process takes place without involvement ofpalladium(0) species.