Total synthesis of (±)-martinellic acid

Abstract

(Matrix Presented) A 14-step synthesis of martinellic acid (1) that proceeds in 3% overall yield has been completed using the reaction of aniline 11 with Meldrum's acid-activated vinylcyclopropane 4 to give vinyl pyrrolidinone 12, condensation of aldehyde 13 with N-benzylglycine to form an azomethine ylide that cyclizes to give 14, selective reduction of 14 to amino alcohol 16 with LiBH4 and MeOH, and guanidine formation by reaction of a cyanamide with 3-methyl-2-buten-1-amine in hexafluoro-2-propanol at 120 °C as key steps.