are investigated acceleration of the electrocyclization of 1,3,5-hexatriene to
1,3-cyclohexadiene through early transition metal catalysis of through quantum mechanical methods [38].
The predominant volatiles in fresh beans of Criollo cacao were hexanal, pentanal, and
1,3-cyclohexadiene, potentially contributing to the almond and grass aroma notes previously reported for raw beans of this cultivar [15].
The mild oxidation of these 1,3-dipoles with N-methyl-morpholine N-oxide (NMO, 1.3 equiv.) is conducted one-pot in the presence of the required trapping diene (freshly distilled cyclopentadiene or 1,3-cyclohexadiene, 2 equiv.) to afford the nitrosocarbonyl HDA cycloadducts 11ad and 12a-d.
1,3-Cyclohexadiene, pyridine-carbaldehyde, 2-quinoline-carbaldehyde, and 4-bromothiazole-2-carbaldehyde were purchased from Sigma-Aldrich.
According to the GC/MS library, furan, 1,3-pentadiene, 2-burene, isoprene, cyclopentene, 3-hexyne, 2,4-hexadiene,
1,3-cyclohexadiene, cyclohexene, and 1-heptene were tentatively identified.
Z-7-tetradecenal (4.98%),
1,3-cyclohexadiene (3.97%), respectively.