Studies toward (−)-Gymnodimine:  Concise Routes to the Spirocyclic and Tetrahydrofuran Moieties

Abstract

[formula: see text] (-)-Gymnodimine is a member of a unique class of potent marine toxins possessing imines within a spirocylic array. Herein we report the synthesis of the tetrahydrofuran fragment and a strategy toward the spirocyclic imine fragment of this family of toxins. Key reactions include an asymmetric anti-aldol reaction to set the stereochemistry of the tetrahydrofuran and a formal, intermolecular Diels-Alder reaction involving an alpha-methylene-delta-lactam and a dienyne.

Reactive organometallics from organotellurides: application in organic synthesis

“…55 The tellurium / lithium exchange reaction was used in the preparation of the pure Z enone 34 (90%), which was converted into a silyl-enol-ether, used as a diene in a DielsAlder cycloaddition, generating a spirolactame 35. 27 This compound was employed in the attempted total synthesis of (-)-gymnodimine 36 (Scheme 17), a marine toxin produced by the dinoflagellate Gymnodinium cf. mikimotoi, found in New Zeeland oysters.…”

“…This toxin is responsible for seafood intoxications, paralytic shellfish poisoning and diarrhetic shellfish poisoning, also called gastroenteritis. 27 A mild alternative to the conventional triple bond reduction was performed by hydrotelluration of a terminal alkyne. The resulting Z-vinyl telluride was treated with two equiv.…”

Practical synthesis of chiral β-telluro amines by ring-opening reaction of aziridines

“…Many different classes of organotellurium compounds have been prepared to date, and vinylic tellurides are certainly the most extensively studied ones, in view of their usefulness in a wide range of applications in organic synthesis [3] and in the total synthesis of natural products [4][5][6]. In addition to their utility in this field, the toxicological and pharmacological aspects of organotellurium compounds have also been recently reviewed [7].…”

Synthesis of spirolactams via Diels-Alder addition of 1,3-butadienes to an α-methylene lactam

“…At the outset of this study the use of α-methylene lactams as dienophiles was rare, 15 however, during the course of this work several communications on the use of α-methylenelactams as dienophiles to construct spirolactams appeared in the literature. 16 We therefore herein report the full details of our preliminary work in this area and offer some improvements to the synthesis of the α-methylenelactam and diene starting materials.…”