Construction of Nitrated Benzo[3.3.1]bicyclic Acetal/Ketal Core via Nitration of <i>o</i>-Carbonyl Allylbenzenes
作者:Chieh-Kai Chan、Yu-Lin Tsai、Meng-Yang Chang
DOI:10.1021/acs.orglett.7b00245
日期:2017.3.17
Intramolecular annulation of o-carbonyl allylbenzenes was achieved to construct novel nitrated [6,6,6]tricycles having an acetal or ketal motif in good yields. The expeditious one-step nitration route provides 4 or 5 new bond formations, including 2 or 3 C–N bonds and 2 C–O bonds. The structural framework of benzobicycle [3.3.1] is confirmed by X-ray crystallographic analysis. A plausible mechanism
Pd(II)-Mediated Cyclization of <i>o</i>-Allylbenzaldehydes in Water: A Novel Synthesis of Isocoumarins
作者:Po-Yuan Chen、Keng-Shiang Huang、Chin-Chuan Tsai、Tzu-Pin Wang、Eng-Chi Wang
DOI:10.1021/ol302256y
日期:2012.9.21
A novel, concise and efficient synthesis of substituted isocoumarins is disclosed. o-Allylbenzaldehydes prepared from isovanillin were mediated by PdCl2-CuCl2 in water to undergo a domino reaction sequence, including 6-exo-trig cyclization, the addition of water, the elimination of PdHCl, the isomerization of carbon-carbon double bond, the oxidation of hemiacetals with the elimination of PdHCl, and regeneration of PdCl2 in situ to yield a series of new substituted isocoumarins in high yields, in one pot.