ChemInform Abstract: Synthesis of Functionalized Hexahydro‐, Octahydro‐, and Decahydro‐1H‐ phenalenes via Diels‐Alder Reactions of 1‐Methylene‐4a‐methoxycarbonyl‐ 1,2,3,4,4a,5,6,7‐octahydronaphthalene and Related Dienes.

Abstract

Synthesis of Functionalized Hexahydro-, Octahydro-, and Decahydro-1H-phenalenes via Diels-Alder Reactions of 1-Methylene-4amethoxycarbonyl-1,2,3,4,4a,5,6,7-octahydronaphthalene and Related Dienes.-Diels-Alder reactions of bicyclic dienes (I) and (V) with a variety of dienophiles are studied with the aim to set the stage for use a similar methodology for effecting the total synthesis of amphilectane-type diterpenoids. Cycloaddition reaction of the dienes with symmetrical dienophiles are highly face-selective furnishing predominantly or even exclusively adducts resulting from the attack of reagents on the β-face of substrate (cf. (III), (VII)). On the other hand, Diels-Alder reactions with unsymmetrical dienophiles are of rather low face-selectivity but high regioselectivity (cf. (IX)-(XI) ). X-ray studies confirm the constitution and stereochemistry of the adducts formed. -(PIERS, E.; FRIESEN, R. W.; KAO, P.; RETTIG, S. J.; TROTTER, J.; Can.