부산대학교 도서관

In this review, the hypercoordination of boron and aluminum as typical main group elements is embodied, and their synthetic utility is demonstrated with several synthetic examples. B and Al Lewis acids are found to be successfully utilized in several chelation-controlled reactions of various substrates (alkoxy carbonyl compounds, fluoro carbonyl compounds, fluoro epoxides, and alkoxy epoxides) via unprecedented pentacoordinate chelate-type complex formation by taking advantage of the exceedingly high affinity of B and Al to fluorine and oxygen, and hence, contrary to the previous observations, can be classified as chelating Lewis acid reagents rather than non-chelating Lewis acids. In addition to the experimental demonstration, such pentacoordinate complex formation of B and Al Lewis acids with various bidentate substrates is also characterized by low-temperature 1H, 13c, 11B, 27AlNMR spectroscopy.