Synthetic studies on valienamine

Abstract

For the synthesis of valienamine 1 and 109, 85 and 120a was proposed as a key intermediate from L-diethyl tartrate and D-galactose respectively. Our initial synthetic scheme includes the intramolecular Baylis-Hillman to form cyclohexane skeleton. A stereoselective introduction of the amino group was achieved via iodocyclization of imidates. In the second approach, an intramolecular aldol condensation was selected to cyclize 138. To obtain 138, Horner-Emmons reaction was utilized with formyl oxazolidine carboxylate (Garner’s aldehyde) 131. This was prepared from L-serine methyl ester hydrochloride.