Preparation and application of chiral spiro nitrogen-containing ligands for cobalt-catalyzed asymmetric Michael addition

Two novel chiral spiro nitrogen-containing ligands, 7,7′-bis(2-pyridinecarboxamido)-1,1′-spirobiindane (abbreviated as SIPAD) and 7,7′-bis(2-quinolinecarboxamido)-1,1′-spirobiindane (abbreviated as SIQAD), were conveniently prepared from 1,1′-spirobiindane-7,7′-dicarboxylic acid in high yields (85% and 84%, respectively) in two steps. The cobalt complexes prepared in situ from Co(OAc)2 and the ligands have been proven to be efficient catalysts for the asymmetric Michael addition reaction of malonates to chalcone derivatives. The alkylation products were obtained in high yields with moderate enantiomeric excesses under mild reaction conditions.

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(S)-1,1′-Spirobiindane-7,7′-diamineC17H18N2Ee = 100%[α]D20=-128 (c 0.2, CH2Cl2)Source of chirality: resolutionAbsolute configuration: S

(S)-7,7′-Bis(2-pyridinecarboxamido)-1,1′-spirobiindaneC29H24N4O2Ee = 100%[α]D20=-364 (c 0.5, CH2Cl2)Source of chirality: resolutionAbsolute configuration: S

(S)-7,7′-Bis(2-quinolinecarboxamido)-1,1′-spirobiindaneC37H28N4O2Ee = 100%[α]D20=-442 (c 0.5, CH2Cl2)Source of chirality: resolutionAbsolute configuration: S

Diethyl 2-[1-(2-chlorophenyl)-3-oxo-3-phenylpropyl]malonateC22H23ClO5Ee = 49%[α]D26=+35.3 (c 0.15, CH2Cl2)Source of chirality: asymmetric catalysis

Diethyl 2-[1-(3-chlorophenyl)-3-oxo-3-phenylpropyl]malonateC22H23ClO5Ee = 53%[α]D26=+17.0 (c 0.5, CH2Cl2)Source of chirality: asymmetric catalysis

Diethyl 2-[1-(3-methoxyphenyl)-3-oxo-3-phenylpropyl]malonateC23H26O6Ee = 49%[α]D26=+12.0 (c 0.5, CH2Cl2)Source of chirality: asymmetric catalysis

Diethyl 2-[3-(3-chlorophenyl)-3-oxo-1-phenylpropyl]malonateC22H23ClO5Ee = 53%[α]D26=+13.4 (c 0.5, CH2Cl2)Source of chirality: asymmetric catalysis

Diethyl 2-[3-(3-bromophenyl)-3-oxo-1-phenylpropyl]malonateC22H23BrO5Ee = 53%[α]D26=+12.4 (c 0.5, CH2Cl2)Source of chirality: asymmetric catalysis

Diethyl 2-[3-(4-nitrophenyl)-3-oxo-1-phenylpropyl]malonateC22H23NO7Ee = 54%[α]D26=+15.0 (c 0.8, CH2Cl2)Source of chirality: asymmetric catalysis

Diethyl 2-[3-(4-methoxyphenyl)-3-oxo-1-phenylpropyl]malonateC23H26O6Ee = 53%[α]D26=+15.0 (c 0.5, CH2Cl2)Source of chirality: asymmetric catalysis

Diethyl 2-[1-(4-nitrophenyl)-3-oxo-3-p-tolylpropyl]malonateC23H25NO7Ee = 51%[α]D26=+19.0 (c 0.2, CH2Cl2)Source of chirality: asymmetric catalysis