Macroporous chiral ruthenium porphyrin polymers: a new solid-phase material used as a device for catalytic asymmetric carbene transfer

A chiral ruthenium porphyrin complex, functionalized with four vinyl groups, has been polymerized with styrene, divinylbenzene (or ethylene glycol dimethacrylate) to obtain supported ruthenium complexes. The asymmetric addition of ethyl diazoacetate (or diazoacetonitrile) to styrene derivatives was carried out by using these polymers as catalysts. The reaction proceeded under mild conditions and gave trans-cyclopropanes with good enantiomeric excess (up to 90%).

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(1S,2S)-(E)-2-phenylcyclopropanecarbonitrileC10H9NEe = 70%[α]D20=+240 (c 0.88, CH2Cl2)Source of chirality: asymmetric synthesisAbsolute configuration: (1S,2S)

(1S,2S)-(E)-2-(4-Methoxyphenyl)cyclopropanecarbonitrileC11H11NOEe = 68%[α]D20=+201 (c 0.50, CH2Cl2)Source of chirality: asymmetric synthesisAbsolute configuration: (1S,2S)

(1S,2S)-(E)-2-(4-Bromophenyl)cyclopropanecarbonitrileC10H8NBrEe = 71%[α]D20=+237 (c 1.20, CH2Cl2)Source of chirality: asymmetric synthesisAbsolute configuration: (1S,2S)