Mechanistic investigation of phosphaalkene mediated alkene formation

SNIC 2018/3-341


SNAC Medium

Principal Investigator:

Andreas Orthaber


Uppsala universitet

Start Date:


End Date:


Primary Classification:

10405: Organic Chemistry



Carbon–carbon double bonds are the functional groups of alkenes and ubiquitous in Nature and commodity chemicals. As such, the discovery of novel synthetic methodologies to construct these bonds from readily available starting materials is at the heart of Organic Chemistry and understanding the involved mechanisms is fundamental to a sound development of new catalytic strategies. Recently, the unprecedented formation of unsymmetrical alkenes from the intermolecular reductive coupling of two different aldehydes was described. In contrast to the McMurry reaction which affords statistical product mixtures, selectivity in the reported procedure is achieved by a sequential – presumably ionic – mechanism in which a first aldehyde is reacted with a phosphanylphosphonate to afford a phosphaalkene intermediate which, upon activation by hydroxide, reacts with a second aldehyde to the unsymmetrical E-alkenes. Recent unpublished work, has shown that the selective formation of E-alkenes can be inverted by alteration of the electronic nature of the utilized aldehyde reagents. It is of general importance to unravel the mechanistic factors that govern the selectivity observed in these reactions. Moreover, the study of other factors that could potentially be varied will help to design new synthetic strategies for this ubiquitous C=C bond formation reactions. Besides the electronic nature of the two aldehydes the nature of the phosphorous containing reagent, the nature of the utilized reagents (Na, K, Li – bases) and solvent influences will be studied. The project stems from a collaboration between the research groups of Dr. Sascha Ott (UU) and Dr. Andreas Orthaber (UU), and is funded by the respective individual project grants to the PIs (VR, ERC, Energimyndigheten, …).