Rhodium-catalyzed hydroformylation of acyclic monoterpenic compounds, i.e., linalool and beta-citronellene, was studied in toluene and ethanol solutions in the presence of PPh3 or P(O-o-(BuPh)-Bu-t)(3) ligands. Although both substrates have a monosubstituted terminal double bond, they show different behavior under the hydroformylation conditions. In toluene, linalool gave almost quantitatively a cyclic hemiacetal: whereas the hydroformylation of beta-citronellene resulted in two isomeric aldehydes also in a nearly quantitative combined yield. The reactions occurred approximately two times faster in ethanol than in toluene giving the corresponding acetals even in the absence of additional acid co-catalysts. In the absence of phosphorous ligands, linalool (differently from beta-citronellene) was very resistant to hydroformylation probably due to the binding with rhodium through both the double bond and the hydroxyl group to form stable chelates. The P(O-o-(BuPh)-Bu-t)(3) ligand exerted a remarkable effect on the reactivity of both substrates accelerating the reactions by 5-20 times as compared to the system with PPh3. Several fragrance compounds were obtained in high yields through a simple one-pot procedure starting from the substrates easily available from natural bio-renewable resources. (C) 2013 Elsevier B.V. All rights reserved.