Palladium-Catalyzed Three-Component Reaction of 3-(Tri-n- butylstannyl)allyl Acetates, Aldehydes, and Triorganoboranes: An Alternative to the Carbonyl Allylation Using α,γ-Substituted Allylic Tin Reagents

Versatile Reactivity of Metalloid-Substituted π-Allylpalladium Species

π-Allylpalladium complexes can not only serve as electrophilic allylating agents for a broad range of nucleophiles, but also nucleophilic allylating agents for electrophiles depending on their electronic environments. In contrast to these typical reactivities of π-allylpalladium complexes, silylated and borylated π-allylpalladium species show unique reactivities that can allow versatile transformations in addition to simple allylation. Herein, four different types of transformations that are in principle achieved via the inherently reactive silylated and borylated π-allylpalladium species as common intermediates are described. An appropriate selection of ligands of the silylated and borylated π-allylpalladium species can allow control over the reaction pathways.

The Synthesis of Chiral β,β-Diaryl Allylic Alcohols and Their Use in the Preparation of α-Tertiary Allylamines and Quaternary α-Amino Acids

An approach to nonracemic β,β-diarylsubstituted allyl alcohols is described. Their synthesis starts from l-lactic acid-derived propargyl alcohol, which is submitted to sequential Sonogashira/Suzuki or Sonagashira/Stille coupling reactions. Both approaches enable the synthesis of either (Z)- or (E)-allylic alcohols regarding the order of introducing coupling agents. The obtained allyl alcohols were applied in the synthesis of nonracemic α-tertiary allylamines via stereocontrolled cyanate-to-isocyanate sigmatropic rearrangement reactions of the corresponding allyl carbamates. The stereoselectivity of the process is controlled by the geometry of the double bond of the starting allyl derivative. As demonstrated, a rearrangement of (S,Z)-allyl carbamates provides (S)-teriary allylamines, whereas the transformation (S,E)-isomers leads to (R)-allylamines.