title: Total synthesis of the monoterpenoid alkaloid (±)-tangutorine.
abstract: A novel approach to a formal total synthesis of the monoterpenoid indole alkaloid (±)-tangutorine has been developed starting from an α,β-unsaturated cyclic dehydroamino ester. Synthesis of the rather unusual trans-substituted 2,3-indoloquinolizidine substructure was accomplished via Cu(II)-mediated conjugate addition and organozinc/copper coupling as the key steps, thereby setting the stage for ring-closing metathesis to produce the quinolone substructure. Finally, Bischler-Napieralski cyclization gave rise to the pentacyclic system of (±)-tangutorine thereby realizing a formal synthesis in an overall yield of 5.2% in eight consecutive steps.
authors: Radboud University Nijmegen, Institute for Molecules and Materials, Heyendaalseweg 135, NL-6525 AJ Nijmegen, The Netherlands.
authors: Sebastiaan A M W
authors: SA
authors: van den Broek
authors: Jaap G H
authors: JG
authors: Lemmers
authors: Floris L
authors: FL
authors: van Delft
authors: Floris P J T
authors: FP
authors: Rutjes
mesh_terms: D000470:Alkaloids / Q000138:chemical synthesis*; D002243:Carbolines / Q000138:chemical synthesis*; D003300:Copper / Q000737:chemistry; D003500:Cyclization; D039821:Monoterpenes / Q000138:chemical synthesis*; D011807:Quinolizines / Q000138:chemical synthesis*; D013237:Stereoisomerism
chemical_list: D000470:Alkaloids; D002243:Carbolines; D039821:Monoterpenes; D011807:Quinolizines; C485396:tangutorine; D003300:Copper