Backbone binaphthalene

In 2004, Shi et al. reported Pd-catalysed asymmetric allylic substitutions using axially chiral S/S- and S/O-heterodonor ligands based on the binaphthalene backbone. The test reaction was performed in the presence of... 

Scheme 1.9 Test reaction with S/S- and S/O-heterodonor ligands with binaphthalene backbone.

As mentioned earlier, a review of key developments in the use of chiral phosphoric acids will be provided by Professor Akiyama in the Chapter 11. It is also worth noting that recent years have seen the development of other strong Bronsted acids with the binaphthalene backbone, such as those by the Yamamoto [182-185], list [186-189], and Toste groups [190]. 

Nevertheless, A 12 proved to be superior in terms of yield and selectivity. The linker between the two sulfonamide moieties was extensively varied. A pentyl chain showed hereby the best outcome. Making use of the chiral l,l -binaphthyl-2,2 -diol (or l,l -binaphthalene-2,2 -diol or l,l -bi-2-naphthol) (BINOL) backbone, Benaglia designed catalyst A 14, which showed excellent yields (98%) and good enantioselectivities (81%). 

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