Complementary asymmetric routes to (R)-2-(7-hydroxy-2,3-dihydro-1H-pyrrolo[1,2-a]indol-1-yl)acetate

Org Lett. 2012 Dec 21;14(24):6306-9. doi: 10.1021/ol303070k. Epub 2012 Dec 4.

Abstract

Two distinct and scalable enantioselective approaches to the tricyclic indole (R)-2-(7-hydroxy-2,3-dihydro-1H-pyrrolo[1,2-a]indol-1-yl)acetate, an important synthon for a preclinical S1P(1) receptor agonist, are reported. Route 1 employs a modified version of Smith's modular 2-substituted indole synthesis as the key transformation. Route 2 involves a highly enantioselective CuH-catalyzed 1,4-hydrosilylation as the stereodefining step. Both routes can be performed without chromatography to provide multigram quantities of the tricycle in ≥98% ee.

MeSH terms

  • Acetates / chemical synthesis*
  • Acetates / chemistry
  • Acetates / pharmacology
  • Catalysis
  • Fingolimod Hydrochloride
  • Indoles / chemical synthesis*
  • Indoles / chemistry
  • Indoles / pharmacology
  • Molecular Structure
  • Propylene Glycols / chemical synthesis
  • Propylene Glycols / chemistry
  • Propylene Glycols / pharmacology
  • Pyrroles / chemical synthesis*
  • Pyrroles / chemistry
  • Pyrroles / pharmacology
  • Receptors, Lysosphingolipid / agonists
  • Sphingosine / analogs & derivatives
  • Sphingosine / chemical synthesis
  • Sphingosine / chemistry
  • Sphingosine / pharmacology
  • Stereoisomerism

Substances

  • (R)-2-(7-hydroxy-2,3-dihydro-1H-pyrrolo(1,2-a)indol-1-yl)acetate
  • Acetates
  • Indoles
  • Propylene Glycols
  • Pyrroles
  • Receptors, Lysosphingolipid
  • Fingolimod Hydrochloride
  • Sphingosine