A New Preparation of 1,3,3‐Trimethylbicyclo[2.2.2]octan‐2,6‐dione, a Never Isolated Intermediate in a Total Synthesis of (+)‐Norpatchoulenol. Formal Total Synthesis of (±)‐Iso‐Norpatchoulenol

Abstract

A new preparation and the isolation and spectroscopic characterization of 1,3,3-trimethylbicyclo[2.2.2]octan-2,6-dione (3), a so far elusive key intermediate in the LiuÀRalitsch total synthesis of ()-norpatchoulenol (()-1a), is described. The preparation of 3 constitutes also a formal total synthesis of (AE)-iso-norpatchoulenol ((AE)-1b), since 3 is correlated to an intermediate in the Monti and co-workers synthesis of (AE)-1b.

Natural sesquiterpenoids

“…305 A formal synthesis of (+)-isonorpatchoulenol has been reported. 339 20 Aromadendrane, myliane, maaliane, aristolane, nardosinane, isogermacrane, iso-a-humulane, iso-b-elemane, gorgonane, zierane and isozierane…”

Asymmetric baker’s yeast reductions of bridgehead-substituted bicyclo[2.2.2]octane-2,6-dione derivatives followed by conversion into catalytically active BODOLs for the diethylzinc addition to benzaldehyde

“…Bicyclo [2.2.2]octanes are often found as subunits in natural products [1][2][3][4][5][6][7][8] and they are frequently used as important building blocks in total synthesis [9][10][11][12][13][14][15] and as ligands in asymmetric catalysis. [16][17][18][19][20][21][22][23][24][25] New applications for bicyclo [2.2.2]octanes are presented continuously.…”