Catalytic Enantio- and Diastereoselective Cyclopropanation of 2‑Azadienes for the Synthesis of Aminocyclopropanes Bearing Quaternary Carbon Stereogenic Centers
journal contributionposted on 29.08.2019, 19:03 by Xinxin Shao, Steven J. Malcolmson
We report the catalytic enantio- and diastereoselective preparation of aminocyclopropanes by the cyclopropanation of terminal and (Z)-internal 2-azadienes with donor/acceptor carbenes derived from α-diazoesters. The resulting cyclopropanes bear quaternary carbon stereogenic centers vicinal to the amino-substituted carbon and are formed as a single diastereomer in up to 99:1 er and 97% yield with 0.5 mol % of Rh2(DOSP)4 and only 1.5 equiv of the diazo reagent. Transformations with internal azadienes afford cyclopropanes with three contiguous stereogenic centers.
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α- diazoesterscyclopropanationmol0.5Rh 2diastereoselective preparationDOSPTransformationamino-substituted carbonaminocyclopropaneDiastereoselective CyclopropanationCatalytic Enantioenantioterminal1.5 equivquaternary carbon stereogenic centers vicinalSynthesidiastereomerdonor2- azadienesAzadieneAminocyclopropanes Bearing Quaternary Carbon Stereogenic Centersstereogenic centersdiazo reagentcarbene