Rational design of dynamic ammonium salt catalysts towards more flexible and selective function

Abstract

This review focuses on the development of dynamic ammonium salt catalysis for selective organic transformations conducted in our laboratory since 2002. Several important concepts in designing of catalysts are described with some examples. In particular, the practial synthesis of chiral 1,1′-binaphthyl-2,2′-disulfonic acid (BINSA) and its application in chiral ammonium salt catalysis for the enantioselective direct Mannich-type reaction are described.

Brønsted Acid/Lewis Base Hybrid Complexes

“…For effective designs of monomeric metal species, 3,3 0 -disubstituted binaphthyl skeletons in BINOL and H 8 -BINOL are the most commonly accepted. In sharp contrast, chiral lithium(I) and magnesium (II) binaphtholates [4][5][6][7][8][9][10][11][12][13][14][15][16][17], which are usually prepared in situ from BuLi or Bu 2 Mg and chiral 3,3 0 -nonsubstituted BINOL or H 8 -BINOL, are practical acidbase combination catalysts [18][19][20][21][22], since the ligands are the simplest and the metals are abundant, inexpensive, harmless, and environmentally benign. However, unsurprisingly, enantioselective induction with high catalytic activity is sometimes problematic, due to their oligomeric or polymeric nature.…”