Total synthesis of [13C4]-anatoxin-a. CSA=10-camphorsulfonic acid, DBU=1,8-diazabicyclo[5.4.0]undec-7-ene, DCC=N,N’-dicyclohexylcarbodiimide, DIPT=diisopropyl tartrate, DMAP=4-(N,N-dimethyl)aminopyridine, HMPA=hexamethylphosphoric triamide, LDA=lithium diisopropylamide, MS=molecular sieves, PPTS=pyridinium p-toluenesulfonate, TEMPO=, Tf=trifluoromethanesulfonyl, THF=tetrahydrofuran, Ts = 4-toluenesulfonyl.