Copper‐Mediated Enantioselective Substitution Reactions

Highly Stereoselective Anti SN2‘ Substitutions of (Z)-Allylic Pentafluorobenzoates with Polyfunctionalized Zinc−Copper Reagents

“…On the other hand, copper-catalyzed allylic substitutions do not suffer from these limitations . They proceed usually with anti S N 2‘ selectivity in cyclic and acyclic systems . The chiral information can be contained either in the allylic electrophile 5 or in a chiral copper catalyst .…”

Cu-Catalyzed Silylation of Alkynes: A Traceless 2-Pyridylsulfonyl Controller Allows Access to Either Regioisomer on Demand

“…This was indeed the case and several terminal propargylic sulfones reacted cleanly under the optimized conditions to afford the corresponding -silylated allylic sulfones (29)(30)(31)(32) in good yields and satisfactory regioselectivities (ranging from 90:10 to >97:<3, Scheme 2).…”

“…The lack of a sterically hindered silyl group at the -allylic position could be the reason behind this SN2'-type selectivity, which on the other hand is typically observed in Cu-catalyzed allylic substitutions. [32] A variety of trisubstituted vinyl silanes with different substitution pattern were obtained regioisomerically pure with acceptable yields in this protocol (products 71-76, 63-75% yields). The compatibility with heteroarenes at the substrate was remarkable (product 71, 75%).…”

Copper‐catalyzed divergent kinetic resolution of racemic allylic substrates

“…However, despite the intrinsic preference for γ‐attack, the regioselectivity can easily be switched between the possible modes by changing the reaction conditions 3. As regard asymmetric processes, the copper‐catalyzed or mediated substitution reactions can be classified into three major types:4 (i) diastereoselective reaction of achiral nucleophiles with chiral substrates, (ii) diastereoselective reaction of chiral nucleophiles with prochiral substrates, and (iii) enantioselective reaction of achiral nucleophiles with prochiral substrates in the presence of chiral catalysts. The last approach, which has the clear advantage that only a small amount of chiral material is required, has recently attracted the interest of several research groups,5–8 and it has been applied extensively and successfully to a variety prochiral substrates with good up to complete regiocontrol and high enantioselectivities 5–11…”