Communication
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References
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Scheme 2 One-step synthesis of jasmine aldehyde 1 and hexyl cinnamaldehyde
2.
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Furthermore, hexyl cinnamaldehyde 2 is a jasminaldehyde-related
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flower compositions and in soap perfumes.9a
For the case of cyclamen aldehyde 3, a number of steps had to
follow our initial cross-aldol condensation (Scheme 3). All of our
efforts for selective hydrogenation of the double bond in the
presence of the carbonyl moiety were met with failure. Among the
methods utilised, transition-metal catalysed hydrogenation and
Hantzsch ester-mediated organocatalytic hydrogenation failed to
deliver the desired product in high yield. Thus, a two-step
hydrogenation–oxidation had to be employed, affording cyclamen
aldehyde 3 in just three steps from commercially available
materials in 34% overall yield.
6 Y. Watanabe, K. Sawada and M. Hayashi, Green Chem., 2010,
12, 384–386 and references therein.
Conclusions
7 L. K. Sharma, K. B. Kim and G. I. Elliot, Green Chem., 2011, 13,
1546–1549 and references therein.
A fast, atom-economic, high-yielding process for the cross-aldol
condensation of aldehydes is described under microwave irradia-
tion. A variety of aldehydes can be utilised and the products are
obtained in good to excellent yields and high to excellent
regiocontrol. Quick and high-yielding access is provided to three
aldehydes: jasminaldehyde 1, hexyl cinnamate 2 and cyclamen
aldehyde 3, which are materials of high significance in the
fragrance industry, via this methodology.
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Scheme 3 Synthesis of cyclamen aldehyde 3.
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