(R)-1-(5-Triisopropylsilanyloxy-furan-3-yl)-2-[(1S,2S,5R,8aR)-1,2,5-trimethyl-5-(4-methyl-pent-4-enyl)-1,2,3,5,6,7,8,8a-octahydro-naphthalen-1-yl]-ethanol