A practical synthesis of racemic heptahelicene has been develeped being based on key [2+2+2] cycloisomerization of bis[2-(but-3-yn-1-yl)-1-naphthyl]acetylene under CpCo(CO)2/PPh3 or CpCo(C2H4)2 catalysis. The application of the Ni(cod)2 catalyst with (-)-(Sa)-(2'-methoxy-1,1'-binaphthalen-2-yl)diphenylphosphane resulted in enantioselective triyne cyclization to provide (+)-7,8,11,12-tetrahydroheptahelicene in 40% ee. Optically pure (-)-(M)- and optically highly enriched (+)-(P)-heptahelicene were obtained on a milligram scale by resolution of racemate by chiral HPLC on a semipreparative Whelk-O1 column.
基于CpCo(CO)2 / PPh3或CpCo(C2H4)2催化剂的双[2-(丁-3-炔-1-基)-1-萘基]乙炔的关键[2 + 2 + 2]环化反应,已经开发出合成外消旋七环螺[4.5]癸烷的实用方法。使用Ni(cod)2催化剂和(-) -(Sa)-(2'-甲氧基-1,1'-联萘-2-基)二苯基膦进行对映选择性的三炔基化反应,得到40%ee的(+) -7,8,11,12-四氢七环螺[4.5]癸烷。通过在半制备Whelk-O1柱上进行手性高效液相色谱分离得到毫克级的光学纯(-) -(M) -和光学高度富集的(+) -(P) -七环螺[4.5]癸烷。