Crotonic acid hydroformylation

Rhodium(I) and cobalt(O) complexes of AMPHOS, [(nbd)Rh(AMPHOS)2] , and [Co(CO)3(AMPHOS)]2(PF6)2, were already being used in the early 1980s for the hydrogenation and hydroformylation of maleic and crotonic acid or styrene and 1-hexene in water or aqueous biphasic systems [49]. The lower effectiveness of the Co catalyst was attributed to the lighter metals proclivity to oxidation and phosphine... 

In 2015, IFF patented the hydroformylation of cyclopentene (Scheme 6.19) [91]. In turn, the formed aldehyde was reacted with MeMgCl to afford the corresponding secondary alcohol. By esterification with crotonic acid, an ester was obtained having fruity, green, fresh, woody spicy, and sweet notes. 

The reactions of ethyl acrylate and ethyl crotonate were studied (117) in the presence of ethyl orthoformate using 1 1 CO/H2 and 250 and 200 atm pressure. For ethyl acrylate, the distribution of products corresponded to j3-hydroformylation 78.2%, (y,y-diethoxybutyrate and j3-formylpropionic acid), and a-hydroformylation 21.7%, (a-methyl-j8-ethoxyacrylate and -methyl-j3,/3-diethoxypropionate). For ethyl crotonate, y-hydroformyla-tion occurred to the extent of 67-73% (8,8-diethoxyvalerate and y-formyl-butyrate) and a-hydroformylation to the extent of only 13.6% (a-ethyl-/ -ethoxyacrylate and j3-ethyl-j8-diethoxypropionate). 

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