Expedient Synthesis of (±)-Bipinnatin J

Abstract

[reaction: see text] A nine-step, stereoselective synthesis of bipinnatin J is described, which features a ruthenium-catalyzed Alder-ene reaction, a Stille cross coupling, and an intramolecular Nozaki-Hiyama-Kishi allylation as key steps. The biosynthetic relationship between bipinnatin J and complex polycyclic diterpenes isolated from gorgonian corals is discussed.

Synthesis of a Highly Functionalized Core of Verrillin

“…To our chagrin, coupling of stannane 10 with primary alcohols 19a and 19b under the previously established Stille conditions (Pd(PPh 3 ) 4 /CuI) 7,10,21 was not successful. However, switching of reagents to catalytic Pd 2 (dba) 3 and triphenylarsine 22 cleanly afforded compounds 20a and 20b in 65% average yield (Scheme 3).…”

“…Stannylation of a transiently protected aldehyde 27 with trimethyltin chloride afforded stannane 10 in 65% yield. 21 In a similar fashion, aldehyde 28 was converted to stannane 29 . 7,21 …”

“…40% yield) (Scheme 5). 7,10,21 Acid-induced MOM deprotection under microwave conditions 27 afforded the corresponding alcohols 32a and 32b in an average yield of 72%.…”

Total (Bio)Synthesis: Strategies of Nature and of Chemists

“…This can be achieved by the development of very specific routes to a single target molecule, like in the recent protective-group-free synthesis of intricarene ( 220 ) (Fig. 38a) [227, 228]. In biosynthesis, final tailoring steps are often used to increase the structural complexity and diversity of a molecule after the production of the central scaffold.…”

Metalated Heterocycles in Organic Synthesis: Recent Applications

“…Lithium-tin exchange afforded the stannyl furfural 175, which has been coupled with the vinyl iodide 176 affording compound 177, an intermediate in the total synthesis of the gorgonian coral metabolite (±)-bipinnatin J. 334 …”