John F. Kingston

Marine natural products. Novel C21Δ20 pregnanes from the sea raspberry (Gersemia rubiformis)

The isolation and structure determination of pregna-1,4,20-trien-3-one (1) and a related sterol, pregna-5, 20-dien3β-ol (2) from an Alcyonacean coral, Gersemia rubiformis are described. These compounds were synthesized from appropriate steroid precursors and the orientation of the C-3 hydroxy-function unambiguously established by preparation of the epimer, pregna-5,20-dien-3α-ol.

Addition initiated ring closure substituted spiro[4,2]Hepta-1,3-dienes via fulvene intermediates

Abstract The reactivity of the epoxy-fulvene 1 with various nucleophiles has been examined. It is a versatile Intermediate for the preparation of spiro[4.2]hepta-1,3-diene synthons via nucleophilic addition to the C6 position followed by intramolecular cyclization of the substituted cyclopentadiene anion generated in situ.

Studies in marine organic chemistry: marine natural products from invertebrates found in newfoundland waters and approaches to the total synthesis of sinularene and 12-acetoxysinularene

Abstract Our recent Studies of marine natural products, particularly steroids 1, 2, 5, 8 and 9, isolated from North Atlantic sponges and alcyonacean corals is reviewed and work in progress directed toward the synthesis of the marine sesquiterpenes, sinularene (18) and 12-acetoxysinularene (17), outlined.

Steroids from the sea raspberry gersemia rubiformiss 24-norcholesta-1,4,22-trien-12β-ol-3-one and its acetate

Abstract Two new 26 carbon steroids with 128 oxygen functions were isolated from the soft coral Gersemia rubiformis and their structures determined from their spectral data and chemical transformations.