The synthesis of volvatellin (4a), previously isolated from a herbivorous marine mollusk, was achieved with high diastereoselectivity from putative dietary oxytoxin-1 (2). A biogenetically patterned carbonyl-ene route was chosen. proceeding from 2 predominantly via the trans cyclization product 3 without the use of enzymes. This challenges the involvement of enzymes in the formation of 4a in nature. The optical purity and absolute configuration (1S,4S,6R). assigned to 3 from high-field H-1-NMR examination of its Mosher (MTPA) esters 6. was retained on its chemical conversion to (+)-(1S,6R)-configured 4a and is consistent with the (4S) configuration previously, established for caulerpenyne (1).
The synthesis of volvatellin (4a), previously isolated from a herbivorous marine mollusk, was achieved with high diastereoselectivity from putative dietary oxytoxin-1 (2). A biogenetically patterned carbonyl-ene route was chosen. proceeding from 2 predominantly via the trans cyclization product 3 without the use of enzymes. This challenges the involvement of enzymes in the formation of 4a in nature. The optical purity and absolute configuration (1S,4S,6R). assigned to 3 from high-field H-1-NMR examination of its Mosher (MTPA) esters 6. was retained on its chemical conversion to (+)-(1S,6R)-configured 4a and is consistent with the (4S) configuration previously, established for caulerpenyne (1).
The synthesis of volvatellin (4a), previously isolated from a herbivorous marine mollusk, was achieved with high diastereoselectivity from putative dietary oxytoxin-1 (2). A biogenetically patterned carbonyl-ene route was chosen. proceeding from 2 predominantly via the trans cyclization product 3 without the use of enzymes. This challenges the involvement of enzymes in the formation of 4a in nature. The optical purity and absolute configuration (1S,4S,6R). assigned to 3 from high-field H-1-NMR examination of its Mosher (MTPA) esters 6. was retained on its chemical conversion to (+)-(1S,6R)-configured 4a and is consistent with the (4S) configuration previously, established for caulerpenyne (1).