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Catalytic Enantioselective Synthesis of the Partially Reduced Tricyclic Pyrrolo[3,2‐ c ]quinoline Core Structure of the Martinella Alkaloids
Author(s) -
Lindbäck Emil,
Sydnes Magne O.
Publication year - 2016
Publication title -
chemistryselect
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.437
H-Index - 34
ISSN - 2365-6549
DOI - 10.1002/slct.201600511
Subject(s) - enantioselective synthesis , quinoline , chemistry , intramolecular force , stereochemistry , trifluoromethanesulfonate , sharpless asymmetric dihydroxylation , catalysis , tricyclic , combinatorial chemistry , organic chemistry
Abstract A catalytic enantioselective synthesis of the hexahydropyrrolo[3,2‐ c ]quinoline core structure found in the Martinella alkaloids, martinelline and martinellic acid, is described. The synthesis is completed without the use of any chiral building blocks or chiral auxiliaries. The key steps in our synthesis constituted a Sp 2 ‐Sp 3 Suzuki‐Miyaura cross‐coupling reaction between a triflate and an N ‐protected β‐aminoethyl boron species to provide a 1,2‐dihydroquinoline carrying a N ‐protected β‐aminoethyl group in the 3‐position, Sharpless asymmetric dihydroxylation of the 1,2‐dihydroquinoline derived from the Suzuki‐Miyaura cross‐coupling reaction, and an acid promoted intramolecular diastereoselective amido cyclisation with the aid of a neighbouring acetoxy group to provide the tricyclic architecture of martinelline and martinellic acid. Our catalytic enantioselective synthesis provided the hexahydropyrrolo[3,2‐ c ]quinoline core structure of the Martinella alkaloids in 75 % ee .