P-carbonyl esters

In addition, 12 was reported to be a suitable organocatalyst for other reactions, including amination of a-cyanoacetates or P-carbonyl esters by reaction with azodi-carboxylate followed by nitrogen-nitrogen bond cleavage of the resultant hydrazine [51]. Recently, a P-isocupreidine with a biphenyl group at C6 instead of a hydroxyl functionality was reported to catalyze the enantioselective [4-1-2] annulation of substituted chromone-3-carbaldehydes and related imines (Scheme 6.22) [52]. 

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