R. Gabaitsekgosi et Cj. Hayes, An alkylidene carbene C-H insertion strategy for the enantioselective synthesis of alpha,alpha-dialkyl-alpha-amino acids, TETRAHEDR L, 40(43), 1999, pp. 7713-7716
A synthesis of the alpha,alpha-dialkyl-alpha-amino acid (1S,3R)-2,5-methano
-leucine has been achieved using an alkylidene carbene 1,5-C-H insertion re
action as a key step. Treatment of the ketone 11 with 1.2 equivalents of li
thio(trimethylsilyl)diazomethane in THF resulted in the formation of the cy
clopentene 13 in 62% yield. The enantiomeric excess of the product 18 was d
etermined to be >95% by chiral HPLC (Chiracel OD column). (C) 1999 Elsevier
Science Ltd. All rights reserved.