Application of Chromium Carbene Complexes

By photolysis of achiral heteroatom-stabilized chromium carbene complexes chromium-ketene species are generated that undergo [2+2] cycloaddition with chiral alkenes diastereoselectively.  

Chromium-complexed ketenes are obtained by irradiation of chromium aminocarbene complexes derived from chiral oxazolidines (CO pressure). These ketenes were found to react with imines diastereoselectively furnishing rram-P-lactams, exclusively.  

Snider in Methods of Organic Chemistry (Houben-Weyl) (Eds. G. Hehnchen, R. W. Hoffinann, J. Mulzer, E. Schaumann), Vol. 21c, Thieme, Stuttgart (1996) 3060 and references cited. 

Thomas, in Recent Progress in the Chemical Synthesis of Antibiotics, (Eds. G. Likacs, M. Ohno), Springer, Berlin (1990) 533. 

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