502-99-8Relevant articles and documents
Asymmetric Total Synthesis and Biosynthetic Implications of Perovskones, Hydrangenone, and Hydrangenone B
Gao, Shuanhu,He, Haibing,Hou, Min,Wen, Guoen,Yang, Baochao,Zhang, Quan
supporting information, p. 6370 - 6375 (2021/05/31)
Perovskones and hydrangenones are a family of structurally complex triterpenoids that were mainly isolated from the genus Salvia medicinal plants. These isoprenoids exhibit a broad range of biological activities, such as antitumor and antiplasmodial activities. Here, we report the collective total synthesis of perovskone, perovskones C, D, F, hydrangenone, and hydrangenone B. The key strategies in this work include the following: (1) an asymmetric photoenolization/Diels-Alder reaction was developed to construct a tricyclic ring bearing three contiguous quaternary centers, which was used to build the core icetexane skeleton; (2) a bioinspired Diels-Alder reaction of perovskatone D with trans-α-ocimene was applied to stereospecifically generate perovskones; (3) late-stage oxidations and ring forming steps were developed to synthesize perovskones and hydrangenones. Our synthetic work suggests that (1) perovskatone D may serve as the precursor of the biosynthesis of perovskones and (2) the formation of hydrangenone and hydrangenone B, containing a five-membered D ring, may involve an oxidative ring cleavage and ring regeneration process.
Photochemical Hydroformylation with Cobalt Catalysts in Methanol
Mirbach, Manfred J.,Topalsavoglou, Nikolaos,Phu, Tuyet Nhu,Mirbach, Marlis F.,Saus, Alfons
, p. 1422 - 1440 (2007/10/02)
The photochemical hydroformylation of 1-octene with cobalt/phosphane complexes in methanol leads under mild conditions (80 deg C, 80 bar CO/H2) with >= 90percent selectivity to linear aldehydes.The reaction rate increases with temperature (Ea = 5 - 6 kcal/mol) and synthesis gas pressure, and is nearly independent of the cobalt source, e.g.Co(OAc)2, Co2(CO)8, or Co2(CO)6(PBu3)2.At low pressures hydroesterification is the preferred photoreaction of 1-octene.Isoprene reacts under similar conditions to give unsaturated oxoproducts and linear isoprene dimers.With unmodified octacarbonyldicobalt the hydroformylation of internal olefins is enhanced by UV light, but not the reaction of terminal olefins or dienes.UV irradiation of cobalt acetate under hydroformylation conditions leads to rapid reduction of the Co(II) species, thus decreasing the induction period from ca. 15 h (without irradiation) to ca. 30 min.
