David M. Pinkerton

Chemoenzymatic access to versatile epoxyquinol synthons.

The enantiomerically pure and readily available metabolites 10-12 have been converted over four simple steps into the epoxyquinol derivatives 22-24, respectively. Compounds 23 and 24 or their immediate precursors have been exploited in efficient total syntheses of (-)-bromoxone (ent-1), (-)-epiepoformin (ent-2), (-)-harveynone (4), (+)-panepophenanthrin (6), and (+)-hexacyclinol (9).

Antimicrobial and cytotoxic activities of synthetically derived Tambjamines C and E-J, BE-18591, and a related alkaloid from the marine bacterium Pseudoalteromonas tunicata.

In the first comprehensive biological assessment of the tambjamine class of marine alkaloids, synthetically derived samples of compounds 1–9 have been subjected to evaluation as antimicrobial agents and screened for their cytotoxic effects on various human cancer cell lines. Most were strongly active against the fungus Malassezia furfur (>amphotericin B) and showed considerable, but non‐selective, antiproliferative activity against both human cancer and normal cell lines. Tambjamines I and J (6 and 7, resp.) displayed significant apoptosis‐inducing effects.

Aryl aldehydes as traceless dielectrophiles in bifunctional titanocene-catalyzed propargylic C-X activations.

The titanocene-catalyzed construction of all-carbon substituted tertiary centers directly from aromatic aldehydes is described. The starting aldehyde behaves as a traceless functionality in the formation of multiple carbon-carbon bonds through consecutive carbon-heteroatom bond activations. The sequential addition of a metal acetylide and a second carbon nucleophile to the dielectrophilic aldehyde enables the construction of symmetrical and unsymmetrical 1,4-diynes in good yields.

Rapid, Chemoenzymatic Syntheses of the Epoxyquinols (-)-Bromoxone Acetate and (—)—Tricholomenyn A

The epoxyquinol derivatives (–)-bromoxone acetate (ent-1) and (–)-tricholomenyn A (2) have been prepared from the cis-1,2-dihydrocatechols 3 and 4, respectively. Compounds 3 and 4 are themselves obtained in enantiomerically pure form through the whole-cell biotransformation of the corresponding halobenzene.

Gaining Synthetic Appreciation for the Gedunin ABC ring system

Gedunin, first isolated in 1960, displays a remarkable range of biological activity, but has yet to receive dedicated synthetic attention from a ground up construction perspective. Presented herein is a successfully executed approach to the fully functionalized ABC ring system of this challengingly complex natural product.