Hydrozirconation/zirconium-zinc transmetalation/aldimine addition: One-pot synthesis of allylic, c-cyclopropylalkyl, and homoallylic amine from alkynes

The Zr-Zn transmetalation, aldehyde addition methodology developed in the Wipf group was extended to the synthesis of allylic amines. The use of toluene as a reaction solvent was required to obtain high yields and low reaction times. N-Phosphinoyl-, N-sulfonoyl-, and N-carbamoylimines were excellent substrates for this transformation. Many chiral ligands were tested for asymmetric catalysis, but minimal ee was achieved. Addition to chiral phosphinimines was also attempted, but the diastereoselectivities were low.; A novel three-component C-cyclopropylalkylamine synthesis was discovered while attempting to perform the allylic amine synthesis in CH2Cl2. The mechanism of this transformation is not fully understood; however, this is the first reported example of a high-yielding Simmons-Smith cyclopropanation with CH2Cl2 as the carbene precursor. This reaction was optimized by adding CH2I2 to the reaction mixture once all imine was consumed. Addition of CH2 I2, prior to imine substrate resulted in homoallylic amine formation.