▁is ▁achieved . ▁ ▁Pan ek ' s ▁ 3 2 ▁step ▁en ant io select ive ▁total ▁synth esis ▁of ▁ans am yc in ▁ant ib i otic ▁(+ )- my cot rien ol ▁makes ▁use ▁of ▁a ▁late ▁stage ▁tan dem ▁St ille ▁type ▁macro cycle ▁coupling . ▁ ▁Here , ▁the ▁organ ost ann ane ▁has ▁two ▁terminal ▁trib ut yl ▁tin ▁groups ▁attacked ▁to ▁an ▁alk ene . ▁ ▁This ▁organ ost ann ane ▁" st ich es " ▁the ▁two ▁ends ▁of ▁the ▁linear ▁starting ▁material ▁into ▁a ▁macro cycle , ▁adding ▁the ▁missing ▁two ▁m eth yl ene ▁units ▁in ▁the ▁process . ▁ ▁After ▁ox id ation ▁of ▁the ▁a rom atic ▁core ▁with ▁cer ic ▁am mon ium ▁nit rate ▁( C AN ) ▁and ▁de prote ction ▁with ▁hydro flu or ic ▁acid ▁yields ▁the ▁natural ▁product ▁in ▁ 5 4 % ▁yield ▁for ▁the ▁ 3 ▁steps . ▁ ▁Stephen ▁F . ▁Martin ▁and ▁cow ork ers ' ▁ 2 1 ▁step ▁en ant io select ive ▁total ▁synth esis ▁of ▁the ▁man z am ine ▁ant it um or ▁al kal oid ▁I rc inal ▁A ▁makes ▁use ▁of ▁a ▁tan dem ▁one - pot ▁St ille / D iels - A lder ▁reaction . ▁ ▁An ▁alk ene ▁group ▁is ▁added ▁to ▁vin yl ▁b rom ide , ▁followed ▁by ▁an ▁in ▁situ ▁D iels - A lder ▁cy clo add ition ▁between ▁the ▁added ▁alk ene ▁and ▁the ▁alk ene