Synthesis, circular dichroism and absolute stereochemistry of 1,1',2,2',3,3',4,4',-octahydro-3,3'-dimethyl-4,4'-biphenanthryl

Abstract

In the course of synthetic studies of chiral olefins, (3R,3'R)-(P,P)-(E)-(-)-1,1',2,2',3,3',4,4'-octahydro3,3'-dimethyl-4,4'-biphenanthrylidene (1) and its (3R, 3'R)-(P,P)-(Z)-(+)-isomer (2), chiral (3R,3'R,4R,4'R)-(-)-1,1',2,2',3,3',4,4'-octahydro-3,3'-dimethyl-4,4'-biphenanthryl (3) was obtained as a by-product in the McMurry reaction of (3R)-(-)-2,3-dihydro-3-methyl-4(1H)-phenanthrenone (4). The relative and absolute stereostructures of (-)-3 were fully determined by NMR, X-ray crystallographic, and CD spectral analyses.