CONDENSED CYCLIC AND BRIDGED-RING SYSTEMS .8. FACTORS INFLUENCING THE STEREOCHEMISTRY OF THE PRODUCTS IN THE ACID-CATALYZED CYCLIALKYLATION REACTIONS OF SOME SUBSTITUTED BETA-PHENYLETHYLCYCLOHEXENE AND BETA-PHENYLETHYCYCLOHEXANOL DERIVATIVES

The distributions of the four possible racemic octahydrophenanthrene derivatives (4, 18, 19, and 20) in the cyclialkylation reaction products from ethyl 1-methyl-2-(β-phenylethyl)cyclohex-2-enecarboxylate (1a), the corresponding exo double-bond isomer lb, and the epimeric lactones of 2-(β-phenylethyl)-3-hydroxy-1-methylcyclohexane-1-carboxylic acid (17a and 17b) using H2SO4-HOAc, PPA, and AICI3-HC1 have been investigated. The diastereomeric cyclic acids were analyzed by 1H NMR spectroscopy and GC of their methyl esters, and were also separated by preparative procedures. H2SO4-HOAc and PPA catalyzed cyclizations of 3β-hydroxy-lα, 3α-dimethyl-2β-(2ʹ-phenylethyl)cyclohexane-1β-carboxylic acid (1 → 3)-lactone (10a) are also described. Based on these experimental data and their comparison with the previously reported results on the formation of the diastereomeric octahydrophenanthrene derivatives 5 and 11a through similar cyclialkylation reactions, consistent mechanisms for these stereochemical results have been advanced. © 1979, American Chemical Society. All rights reserved.