Isoaltholactone

Tetrahedron Letters.2003 July 28;44(31):5831–5833.

A concise and stereoselective synthesis of both enantiomers of altholactone and isoaltholactone.[Reference: WebLink]

METHODS AND RESULTS:
A concise and flexible stereoselective route to synthesize both enantiomers of the highly functionalized α,β-unsaturated-δ-lactones, altholactone and Isoaltholactone, from readily available cinnamyl alcohol is described. This approach derived its asymmetry from Sharpless catalytic asymmetric epoxidation and Sharpless asymmetric dihydroxylation reactions.
CONCLUSIONS:
The resulting diols were produced in high enantiomeric excess and were cyclized in a stereoselective manner in the presence of a catalytic amount of camphor sulphonic acid.

European Journal of Organic Chemistry. 2011 Dec; 2011(36).

Stereoselective Synthesis of Aza Analogues of Isoaltholactone and Goniothalesdiol - New Applications of the Heck-Matsuda Reaction.[Reference: WebLink]

The stereoselective synthesis of nitrogen analogues of biologically active Isoaltholactone and goniothalesdiol are described.
METHODS AND RESULTS:
The successful strategy employed a Heck–Matsuda reaction between a chiral endocyclic enecarbamate bearing an ester functionality and arenediazonium tetrafluoroborates in a divergent approach at an early stage of the synthesis. Several aspects related to this critical arylation reaction are discussed to highlight structural features that affect the outcome of the arylation process. The synthesis of (–)-aza-Isoaltholactone 6 was successfully accomplished in nine steps from the starting enecarbamate. We also performed the synthesis of the new fully substituted pyrrolidine (–)-(2R,3R,4S,5S)-1-(tert-butoxycarbonyl)-3,4-dihydroxy-5-phenylpyrrolidin-2-ylacrylic acid 28, which is a potential advanced intermediate in the route to aza-altholactone. Moreover, the synthesis of a new nitrogen analogue of goniothalesdiol (+)-33 was accomplished from the protected dihydroxypyrrolidine (–)-27, obtained from an attempted synthesis of aza-altholactone.