Brønsted Acid‐Catalyzed Three‐Component Hosomi–Sakurai Reactions

Abstract

Aldehydes react with silyl ethers or the corresponding alcohols and allylsilanes in the presence of catalytic amounts of 2,4-dinitrobenzenesulfonic acid (DNBA) to provide a wide range of homoallylic ethers in moderate to high yields.

Chiral 1,1′‐Binaphthyl‐2,2′‐Disulfonic Acid (BINSA) and Its Derivatives for Asymmetric Catalysis

“…At almost the same time as Ishihara and co-workers report, [9] List and co-workers independently reported the catalytic asymmetric acylcyanation of aldimines with pyruvonitrile (14) and Hosomi-Sakurai reactions between aldehydes, silylethers 16, and allylsilanes 17 in the presence of (R)-6 (Scheme 6). [10] However, enantioselectivity was not induced (< 5 % ee) in these reactions. .…”

“…)/ KOH, and protonation by ion exchange provided (R)-6 on greater than 10 g scale without a loss of optical purity. Sumitomo Chemical reported a patent in 2008, the same year as Ishiharas [9] and Lists [10,11] reports (Scheme 3, Eq. (1)).…”

A Powerful Chiral Counteranion Motif for Asymmetric Catalysis

“…Recently, a highly acidic binaphthyl‐derived chiral disulfonic acid catalyst has been designed and synthesized 28–30. The corresponding chiral cyclic disulfonimides have been unknown but appeared to us as a particularly promising chiral catalyst motif 31.…”

A Powerful Chiral Counteranion Motif for Asymmetric Catalysis

“…[25][26][27] Recently, a highly acidic binaphthyl-derived chiral disulfonic acid catalyst has been designed and synthesized. [28][29][30] The corresponding chiral cyclic disulfonimides have been unknown but appeared to us as a particularly promising chiral catalyst motif. [31] We were fascinated with the possibility that chiral binaphthyl-derived sulfonic acids and disulfonimides may resemble the relative reactivity of triflic acid (TfOH) and of triflylimide (Tf 2 NH), which are both powerful Brønsted acid catalysts.…”