Crystal and Molecular Structure of Sclerophytin F Methyl Ether from the Soft Coral Cladiella krempfi

Abstract

A new cembranoid diterpene was isolated from the soft coral Cladiella krempfi from Minicoy Island (India), and its structure was established by X-ray crystallography to be sclerophytin F methyl ether {2] with the R absolute configuration at all six epimeric centers, assuming a configuration similar to that of sclerophytin C. Compound 2 may be an artifact of the isolation process.Novel sterols, prostaglandins, and especially cembranoid diterpenes have been reported from alcyonarian soft corals and gorgonians of the phylum Coelenterata. Natural products produced

The sclerophytin A adventure

“…The structural definition and absolute stereochemistry of sclerophytins E and F, previously reported to be 48 and 49 ,33 must now be regarded as necessarily incompatible with the revised structural assignments to sclerophytins A and B confirmed herein. While these two members of the series require reinvestigation, the congeners known as patagonicol ( 50 )34 and sclerophytin F methyl ether ( 51 )35 do not, as X‐ray crystallographic corroboration is again in place. Attention is called to the stereoreversed nature of the configuration at C‐3 in 51 .…”

Eunicellin-Based Diterpenoids, Hirsutalins S–V, from the Formosan Soft Coral Cladiella hirsuta

“…The chemical investigations on soft corals of the genus Cladiella and Klyxum [ 1 , 2 , 3 , 4 , 5 , 6 , 7 , 8 , 9 , 10 , 11 , 12 , 13 , 14 , 15 , 16 , 17 , 18 , 19 , 20 , 21 , 22 , 23 , 24 , 25 , 26 , 27 , 28 , 29 , 30 , 31 , 32 ] have afforded series of eunicellin-based diterpenoids, of which many have been shown to exhibit attracting biological activities [ 8 , 10 , 11 , 12 , 13 , 14 , 15 , 16 , 17 , 18 , 19 , 20 , 21 , 22 , 23 , 24 , 25 , 26 , 27 , 28 ,…”

Eunicellin-Based Diterpenoids, Hirsutalins N–R, from the Formosan Soft Coral Cladiella hirsuta

“…The chemical investigations on soft corals of the genus Cladiella and Klyxum [ 1 , 2 , 3 , 4 , 5 , 6 , 7 , 8 , 9 , 10 , 11 , 12 , 13 , 14 , 15 , 16 , 17 , 18 , 19 , 20 , 21 , 22 , 23 , 24 , 25 , 26 , 27 , 28 , 29 , 30 ] have afforded several eunicellin-based diterpenoids, of which many have been shown to exhibit interesting bioactivities [ 8 , 10 , 11 , 12 , 13 , 14 , 15 , 16 , 17 , 18 , 19 , 20 , 21 , 22 , 23 , 24 , 25 , 26 , 27 , 28 , 29 , 30 ]. Our recent chemical study of a Ta...…”