An unprecedented hydroalkylation of racemic allylic alcohols and racemic ketimine esters enabled by Cu/Ru relay catalysis has been developed via merging the ruthenium-catalyzed asymmetric borrowing-hydrogen reaction with a copper-catalyzed asymmetric Michael addition in a one-pot procedure. The current method enables the efficient preparation of highly functionalized δ-hydroxyesters bearing 1,4-nonadjacent stereocenters in good yields with high levels of diastereoselectivity and excellent enantioselectivity under mild reaction conditions. The full complement of the four stereoisomers of hydroalkylation products could be readily accessed by orthogonal permutations of two chiral metal catalysts. The current work highlights the power of relay catalysis for the stereodivergent construction of 1,4-nonadjacent stereocenters that were otherwise inaccessible.
The synergistic chiral Lewis acid/achiral
Pd catalyst system was
successfully applied in the enantioselective benzylation of various
imine esters, giving a range of α-benzyl-substituted α-amino
acid derivatives in satisfactory yield with excellent enantioselectivity.
It is worth noting that this strategy exhibits good tolerance for
bicyclic and monocyclic benzylic electrophiles. Furthermore, the utility
of this synthetic protocol was demonstrated by the expedient preparation
of enantioenriched antihypertensive drug α-methyl-l-dopa.
An unprecedented hydroalkylation of racemic allylic alcohols and racemic ketimine esters enabled by Cu/Ru relay catalysis has been developed via merging the ruthenium-catalyzed asymmetric borrowing-hydrogen reaction with a copper-catalyzed asymmetric Michael addition in a one-pot procedure. The current method enables the efficient preparation of highly functionalized δ-hydroxyesters bearing 1,4-nonadjacent stereocenters in good yields with high levels of diastereoselectivity and excellent enantioselectivity under mild reaction conditions. The full complement of the four stereoisomers of hydroalkylation products could be readily accessed by orthogonal permutations of two chiral metal catalysts. The current work highlights the power of relay catalysis for the stereodivergent construction of 1,4-nonadjacent stereocenters that were otherwise inaccessible.
A series of benzofulvenes without any electron-withdrawing substituents were employed as 2π-type of dipolarophiles for the first time to participate in Cu(I)-catalyzed asymmetric 1,3-dipolar cycloaddition (1,3-DC) reactions of azomethine ylides....
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