Access to a guanacastepene and cortistatin-related skeleton via ethynyl lactone ireland–claisen rearrangement and transannular (4 + 3)-cycloaddition of an azatrimethylenemethane diyl

DOI: 10.1021/acs.orglett.7b00834

Authors: Oleksandr Zhurakovskyi (University of Oxford) , Sam R. Ellis (University of Oxford) , Amber Thompson (University of Oxford) , Jeremy Robertson (University of Oxford)
Co-authored by industrial partner: No

Type: Journal Paper
Journal: Organic Letters

State: Published (Approved)
Published: April 2017
Diamond Proposal Number(s): 7768

Abstract: Heating a 2,5-furanocyclic (2-azidoethyl)allene initiates a cascade reaction comprising azide–allene cycloaddition, loss of nitrogen, and azatrimethylenemethane (ATMM) diyl–furan transannular (4 + 3)-cycloaddition. The major product of this reaction contains the pentacyclic core common to guanacastepenes D and H and radianspenes J–L; in addition, the central oxa-bridged cycloheptene ring, flanked by two carbocyclic rings, is structurally related to the ABC-ring system found in the cortistatins. This is the first reported synthetic application of a “free” (nonconjugated) ATMM. The cyclization precursors were prepared via the first reported examples of the Ireland–Claisen rearrangement of an ethynyl lactone.

Journal Keywords: Hydrocarbons; Organic compounds; Rearrangement; Allenes; Cyclization

Subject Areas: Chemistry


Instruments: I19-Small Molecule Single Crystal Diffraction

Added On: 18/04/2017 10:18

Discipline Tags:

Chemistry Organic Chemistry

Technical Tags:

Diffraction Single Crystal X-ray Diffraction (SXRD)