Methodology for the construction of quaternary carbon centers

The first enantioselective total synthesis of scopadulcic acid A is described. The key step is a cascade intramolecular Heck reaction of a methylenecycloheptene iodide, which generates the B, C, and D rings of the scopadulan ring system in 90% yield as a single stereoisomer. A distinctive feature of these syntheses is the use of stereoselective enolization to dictate which enantiomer of the natural product is produced.

Enantiodivergent Total Syntheses of (+)- and (−)-Scopadulcic Acid A

Decomposition of vinyldiazoacetates by rhodium(II) (N-dodecylbenzenesulfonyl)prolinate (Rh2(S-DOSP)4, 1) in the presence of dienes results in a direct and highly enantioselective method for the formation of cis-divinylcyclopropanes. Combination of this process with a subsequent Cope rearrangement results in a highly enantioselective synthesis of a variety of cycloheptadienes containing multiple stereogenic centers.

Tandem Asymmetric Cyclopropanation/Cope Rearrangement. A Highly Diastereoselective and Enantioselective Method for the Construction of 1,4-Cycloheptadienes

Michael A. Eissenstat

Papers

A general methodology for pseudoguaiane synthesis: total synthesis of (.+-.)-damsinic acid and (.+-.)-confertin

A general methodology for pseudoguaiane synthesis: total synthesis of (.+-.)-damsinic acid and (.+-.)-confertin