Total Synthesis of (+/-)-Celacinnine, (+/-)-Celallocinnine, (+/-)-Celafurine, and (+/-)-Celabenzine

Article abstract of DOI:10.1021/ja00410a025

The total synthesis of spermidine alkaloids, (+/-)-celacinnine (2), (+/-)-celallocinnine (3), (+/-)-celafurine (4), and (+/-)-celabenzine (5), is described.The use of boron-templated cyclization within the context of constructing macrolactam has been explored, and the combination of triamino ester with tris(dimethylamino)borane is found to be highly efficient.The present cyclization in addition to the refinement of each step produces macrocyclic spermidine alkaloids, 2, 4, and 5, by a five-step sequence in ca. 41percent overall yield starting from 1,4-diaminobutane.Irradiation of 2 affords 3 in 50percent yield.