An alkylidene carbene C-H insertion strategy for the enantioselective synthesis of α,α-dialkyl-α-amino acids

Article abstract of DOI:10.1016/S0040-4039(99)01613-5

A synthesis of the α,α-dialkyl-α-amino acid (1S,3R)-2,5-methano-leucine has been achieved using an alkylidene carbene 1,5-C-H insertion reaction as a key step. Treatment of the ketone 11 with 1.2 equivalents of lithio(trimethylsilyl)diazomethane in THF resulted in the formation of the cyclopentene 13 in 62% yield. The enantiomeric excess of the product 18 was determined to be >95% by chiral HPLC (Chiracel OD column).