Synthesis and reactivity of 4-oxo-5-trimethylsilanyl derived a-amino acids

A Lewis-acid promoted one-carbon homologation of an aspartic acid semialdehyde with trimethylsilyldiazomethane has led to the efficient synthesis of two silicon-containing a-amino acids. The use of trimethylaluminium or catalytic tin(II) chloride gave novel 4-oxo-5-trimethylsilanyl derived amino acids in yields of 71e88%. An investigation into the reactivity of these highly functional a-amino acids showed that selective cleavage of the CeSi bond could be achieved under mild basic conditions to give a protected derivative of the naturally occurring amino acid, 4-oxo-L-norvaline. Alternatively, Peterson olefination with aryl or alkyl aldehydes resulted in the formation of E-enone derived a-amino acids. 2014 The Authors. Published by Elsevier Ltd. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/3.0/). Fig. 1. Silicon-containing a-amino acids and peptides.