Phthaloyl aspartic acid

The reaction of nickelacycle 66 with CO and r-BuCN proceeds in the same way after addition of (PhCOO)2 and gives phthaloyl aspartic acid and phthaloyl t-butylasparagine after acid hydrolysis, respectively. Besides insertion of CO and RNC, the nickelacycles also react with some alkynes. Reaction of in situ generated 66 with phenylacetylene at room temperature, followed by acid hydrolysis, leads to a 1.5 1 mixture of 74 and 75 with 83% yield (Eq. 27). When this reaction is performed at 66... 

The alkylation reactions proceed with moderate to good yields with primary iodides (Entries 1,3,6, and 7) or bromides (Entries 2,4, and 5) in the absence of additives or polar solvents. The only byproducts detected were small amounts of ( )-a- and P-A -phthaloyl alanines and ( )-A -phthaloyl aspartic acid. In a few instances, small amounts of A Vinylphthalimide, resulting from double decarboxylation, were also detected. Shorter reaction times were required when the reaction was performed at 40 °C. Secondary iodides also gave alkylated derivatives (Entries 8 and 9). However, no alkylation was observed when more hindered substrates, such as a-cholestanyl iodide and menthyl iodide or bromide were used. These halides were recovered unchanged or suffered elimination to afford mixtures of alkenes after several days at room temperature. On the other hand, no alkylation took place with methyl p-toluenesulfonate, ethyl triflate, and propylene oxide under the same reaction conditions. Similarly, alkenyl and aiyl halides were unreactive with nickelacycles. 

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