A convergent synthesis of triquinane sesterterpenes. Enantioselective synthesis of (-)-retigeranic acid A

Evolution of a Unified Strategy for Complex Sesterterpenoids: Progress toward Astellatol and the Total Synthesis of (−)‐Nitidasin

“…[12] This might be because of the challengesa ssociated with the synthesis of the polycarbocyclic ring-systems. Only the laboratories of Corey, [13] Paquette, [14] Hudlicky, [15] and Wender [16] succeeded in the total synthesis of retigeranic acid A. Apart from thesei mpressivea chievements, the laborotories of Paquette [17] and Dake [18] reported the construction of the carbon framework of aleurodiscal and nitiol, respectively,a nd Tori and co-workers approached the YW-3699 skeleton, without addressing the hydrindane portion.…”

Stereoselective Synthesis of Bicyclo[4.2.1]nonanes – a Temporary‐Bridge Approach to Cyclooctanoids

“…We then looked for an alternative protocol for the 1,3‐ester shift in 2a involving a retro‐Dieckmann fragmentation/Dieckmann cyclization as described by Isida and co‐workers 18. It is of importance that the coupling of the 1,3‐shift of the ester group with the direct alkylation of the resulting enolate was later proven possible by Dauben and co‐workers in their synthesis of fenestranes19a and by Paquette and co‐workers in their related work on triquinane synthesis 19b. Thus, we found that the desired synthesisof 3a could be realized very efficiently from 2a by usinga domino, anionic, ring‐cleavage/ring‐reconstitution/alkylation sequence including a 1,3‐shift of the ester group (Scheme ).…”

Algorithmic Discovery of Tactical Combinations for Advanced Organic Syntheses

“…Examples of Tactical Combinations Unknown in the Literature (A) A sequence of exo-5-trig radical cyclisation followed by tandem Birch reduction and hydrolysis of an enol ether constructs a cis-tricyclic ring system, found in the triquinane sesterterpenes. 25,26 (B) Formation of the tetrahydropyran ring in the first retrosynthetic step sets the scene for the intramolecular, enantioselective hydroalkylation reaction, which installs two stereocenters. The structural motif produced by this sequence of reactions can be used in the synthesis of 3,4-disubstituted piperidine scaffolds 27 often present in biologically active compounds such as famoxetine.…”