Total Synthesis of (±)-Leonuketal

Phillip S Grant; Daniel P Furkert; Margaret A Brimble

doi:10.1021/acs.orglett.0c03364

Total Synthesis of (±)-Leonuketal

Org Lett. 2020 Nov 6;22(21):8735-8740. doi: 10.1021/acs.orglett.0c03364. Epub 2020 Oct 21.

Authors

Phillip S Grant^{1

2}, Daniel P Furkert^{1

2}, Margaret A Brimble^{1

2}

Affiliations

¹ School of Chemical Sciences, University of Auckland, 23 Symonds Street, Auckland 1010, New Zealand.
² Maurice Wilkins Centre for Molecular Biodiscovery, 3 Symonds Street, Auckland 1010, New Zealand.

PMID: 33086011
DOI: 10.1021/acs.orglett.0c03364

Abstract

Leonuketal is an 8,9-seco-labdane terpenoid with a unique tetracyclic structure, owing to a diversity-generating biosynthetic C-C bond cleavage event. The first total synthesis of leonuketal is reported, featuring a Ti(III)-mediated reductive cyclization of an epoxy nitrile ether, an unusual ring-opening alkyne formation as part of an auxiliary ring strategy, and the previously undescribed Au(I)-catalyzed cyclization of a β-keto(enol)lactone to assemble the core spiroketal motif.