245678-49-3Relevant articles and documents
Absolute configuration and total synthesis of (-)-cabenegrin A-I
Tokes, Adrienne L.,Litkei, Gyoergy,Gulacsi, Katalin,Antus, Sandor,Baitz-Gacs, Eszter,Szantay, Csaba,Darko, Laszlo L.
, p. 9283 - 9296 (2007/10/03)
The total synthesis of (-)-cabenegrin A-I [(-)-1] in five steps was achieved from (-)-6aR, 11aR-maackiain [(-)-5], which in turn was prepared by the optical resolution of racemic (±)-5 using S-(-)α-methylbenzyl isocyanate as the the chiral auxiliary. The homochirality of(-)-maackiain [(- )-5] and (-)cabenegrin A-I [(-)-1] was proved by CD measurements. Synthesis of (±)maackiain [(±)-5] is also presented, starting from the readily available phenol derivatives resorcinol and sesamol, which demonstrates the synthetic utility of the Heck-type oxyarylation process for obtaining pterocarpane derivatives on a multigram scale. A new ring-opening reaction of pterocarpanes (7 → 28) is described.