SYNTHESIS OF (+)-CIS-1-METHOXY-4BETA-CARBOMETHOXY-4A,5,8,8A-TETRAHYDROISOCHROMAN, A SYNTHON FOR THE PREPARATION OF ALKALOIDS AND IRIDOIDS

A synthesis of (+)-cis-lβ-methoxy-4β-carbomethoxy-4a, 5, 8, 8a-tetrahydroisochroman (3b) is carried out in seven steps from furfuryl alcohol in 8-16% overall yield. Detailed analyses of the 1H NMR spectra of two intermediates prepared during this synthesis, 5b and 1α-OMe-6b, plus other chemical evidence reveal that a preliminary report7 concerning the preparation of 3b and 5b contained an incorrect assignment of relative stereochemistry. The results of the present study enable a correction of one literature report8 describing the synthesis of 5b. The bicyclic compound 3b represents a potentially useful synthon for the preparation of certain indole alkaloids and iridoids. © 1979, American Chemical Society. All rights reserved.