Catalytic asymmetric ylide generation and subsequent transformation via chiral metal carbene intermediates

Abstract

The tandem ylide generation and rearrangement or cycloaddition sequence triggered by copper(I) or dirhodium (II) complex-catalyzed decomposition of α-diazo carbonyl compounds has recently found numerous applications in organic synthesis. While exceptionally high levels of enantiocontrol in C-H insertions and cyclopropanations have already been achieved using well-designed chiral metal catalysts, the development of an enantioselective version of this process has not been so straightforward as it was believed until several years ago that the reactions of ylides would occur from the free ylide detached from the catalyst rather than from the metal complex-associated ylide. The rapid recent developments in this area reviewed here have shown that high levels of asymmetric induction are possible with rearrangements of oxonium ylides and with 1,3-dipolar cycloadditions of carbonyl ylides where the chiral metal catalyst can remain bound to the ylides in the product-forming step.