Cinnamaldehydes solid support

Pihko and co-workers reported asymmetric organocatalytic Diels-Alder reactions on solid support (JandaJel -supported or n-propyl-functionalized silica gel) with the advantage of easy recovery and reuse, Scheme 3.22 [36]. For example, synthesized polymer- and siUca-supported chiral imidazolidinone catalysts 55 and 56 were demonstrated to be efficient catalyst for the enantioselective Diels-Alder reactions of cyclopentadiene and cinnamaldehyde. 

The relatively inexpensive and safe sodium borohydride (NaBH4) has been extensively used as a reducing agent because of its compatibility with protic solvents. Varma and coworkers reported a method for the expeditious reduction of aldehydes and ketones that used alumina-supported NaBH4 and proceeded in the solid state accelerated by microwave irradiation (Scheme 7) [50]. The chemoselectivity was apparent from the reduction of frarcs-cinnamaldehyde to afford cinnamyl alcohol. 

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