Ph.D. Thesis_AS_Publishing version for IRC_12 ... - Jacobs University

Chapter 1
1.4.2.3 Amino-sulfonamides, amino-thiophosphoramide and amino-amides
Unlike thiourea-based catalysts, these catalysts contain only one hydrogen bond donor site,
whereas like thiourea-based catalysts contain a static hydrogen bond donor. In the mechanism for
these types of bifunctional catalsyts, the acidic N-H group is used for eletrophile attraction.
Examples are shown in Figure 1.4. Here, I will discuss saveral examples of this category.
Wang and coworkers 26 used catalyst 21 (Figure 1.4) for asymmetric Michael addition of
aldehydes (unbranched and α-branched) and ketones (cyclic and acyclic) to various nitroalkenes.
Overall, they had excellent product profiles but their catalyst fails to show reaction progress when
using cyclopentanone as a Michael donor. Under the same reaction conditions, they obtained only
11% yield without any chiral induction.
Headley (2009) 27 used catalyst 22 (Figure 1.4) for asymmetric Michael additions to nitroolefins.
They demonstrated examples of ketone additions to nitroolefins and got up to 97% isolated yield
with 99% ee and 99:1 dr. Using cyclopentanone as Michael donor, they obtained a negligible
results, in 36 h only 10% conversion without chiral induction.
Recently, Wang and Zhou 24c reported a new primary amine-thiophosphoramide bifunctional
catalyst (Figure 1.4, 24) for the asymmetric Michael addition. They had better results with their
catalyst (97 to >99% ee and upto >99% yield) for the asymmetric Michael addition of acetone to
nitroolefins. Their main disadvantage was that they used only acetone as Michael donor in their
reactions.
Cόrdova 24b was the first to demonstrate enantioselective Michael additions catalyzed by simple
amino amide derivatives. He screened 15 different derivatives and found that only one of them
showed prominent results for the addition of various cyclic and acyclic ketones to nitroolefins
(Figure 1.4, 25).
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