Palladium-Catalyzed Stereoselective Synthesis of (E)-Stilbenes via Organozinc Reagents and Carbonyl Compounds
作者:Jin-Xian Wang、Kehu Wang、Lianbiao Zhao、Hongxia Li、Ying Fu、Yulai Hu
DOI:10.1002/adsc.200606016
日期:——
In the presence of a catalytic amount of PdCl2(PPh3)2 and a silylating agent, organozinc halides reacted with carbonylcompounds to give the corresponding (E)-stilbenes in good to excellent yields under mild conditions. The reaction mechanism is briefly discussed.
3,6,8-tetrabromopyrene with 4-[(–)-β-citronellyloxy]phenylethyne was employed to synthesize 1,3,6,8-tetra[4-(citronellyloxy)phenylethynyl]pyrene. The pyrene derivative catalyzed the reductive desulfonylation of ethenyl sulfones via visible-light irradiation (514 nm green light-emitting diodes) in the presence of i-Pr2NEt. The β-citronellyloxy groups provided the sufficient solubility to the highly
Diarylethenes were obtained from the corresponding ethenyl sulfones by photocatalyzed desulfonylation using UV or blue LEDs. When perylene and i-Pr2NEt were used as a photocatalyst and a sacrificing reagent, respectively, this desulfonylation proceeded smoothly to afford the desired ethenes with the functional groups such as chloro, alkoxy and heteroaromatic rings remaining untouched. The use of a flow photoreactor enabled this desulfonylation to proceed more rapidly to finish in an hour of residence time.
Novel nonsteroidal C(17,20)-lyase inhibitors were synthesized using denovodesign based on its substrate, 17 alpha-hydroxypregnenolone, and several compounds exhibited potent C(17,20)-lyase inhibition. However, in vivo activities were found to be short-lasting, and in order to improve the duration of action, a series of benzothiophene derivatives were evaluated. As a result, compounds 9h, (S)-9i,
stabilizers for Pd nanoparticles (Pd NPs), and the obtained materials have been characterized by means of analytical and spectroscopic techniques and then employed as easily recoverable and recyclable catalysts for Suzuki and Heck reactions. Quantitative conversions have been obtained in almost all the explored reactions, even employing low loading of catalyst (down to 0.007 mol%). Suzukireactions were carried