Darren Poole

As an alternative to conventional asymmetric hydroformylation (AHF), asymmetric transfer hydroformylation (ATHF) by using formaldehyde as a surrogate for syngas is reported. A catalyst derived from commercially available [Rh(acac)(CO)₂] (acac=acetylacetonate) and 1,2-bis[(2S,5S)-2,5-diphenylphospholano]ethane(1,5-cyclooctadiene) (Ph-BPE) stands out in terms of both activity and enantioselectivity. Remarkably, not only are high selectivities achievable, the reactions are very simple to perform, and higher enantioselectivity (up to 96 % ee) and/or turnover frequencies than those achievable by using the same catalyst (or other leading catalysts) can be obtained by using typical conditions for AHF.

A surrogate that surpasses the original: An asymmetric transfer hydroformylation (ATHF) of alkenes has been developed using solid paraformaldehyde as a surrogate. Better enantioselectivities and/or turnover frequencies can be obtained than the conventional hydroformylation of the same substrates (see scheme).

We have successfully demonstrated that in the presence of N,N-diisopropylethylamine, copper iodide could efficiently catalyze the coupling of internal propargylic alcohols with carbon dioxide to afford the corresponding α-alkylidene cyclic carbonates in moderate to excellent yields. Moreover, we have developed a new and versatile protocol for the chemo- and stereoselective synthesis of a wide range of (E)-α-iodoalkylidene cyclic carbonates from carbon dioxide, propargylic alcohols and potassium iodide using copper salt as the promoter. The process is proposed to proceed through the trapping of the vinyl copper intermediate by in situ generated triiodide ion as electrophile.