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

Chapter 1
H
O
O
Ph
N
O
Catalyst (10 mol%)
CHCl3, rt, 24h
H
O
O
O
N
Yield = 40%
ee = 51%
Ph
N
H
Catalyst
Ph
Ph
OTMS
Scheme 1.15. Example of asymmetric Michael addition of α-substituted aldehydes to
maleimides.
After this first demonstration, four more attempts are reported 25c,48 for the synthesis of similar
Michael products, to achieve excellent products profile, but unfortunately they didn't achieve this
goal. Interestingly, all four reports used a monothiourea of trans-1,2- diaminocyclohexane as
catalyst (Figure 1.3, 14, 15 and 16). A product summary of those reports is shown in Table 1.4.
Figure 1.11 shows α-substituted aldehydes examined in asymmetric Michael additions to
maleimides.
α-substituted aldehydes
O
O
O
O
O
H
H
H
H
H
Ph
68 69 70 71 72
O
O
O
O
O
H
H
H
H
H
O
73 74 75
O
76 77
Figure 1.11. α-substituted aldehydes used in asymmetric Michael additions to maleimides.
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