85565-94-2Relevant academic research and scientific papers
Total Synthesis of (±)-Pestalachloride C and (±)-Pestalachloride D through a Biomimetic Knoevenagel/Hetero-Diels-Alder Cascade
Arredondo, Vanessa,Roa, Daniel E.,Yan, Songyuan,Liu-Smith, Feng,Van Vranken, David L.
, p. 1755 - 1759 (2019)
A concise total synthesis of (±)-pestalachloride C and (±)-pestalachloride D was achieved through a Knoevenagel/hetero-Diels-Alder cascade reaction to test the nonenzymatic biosynthetic hypothesis of Shao, Wang, and co-workers. The cascade reaction generates a mixture of racemic indano[2,1-c]chromans like those found in the natural products.
Polycationic ligands in gold catalysis: Synthesis and applications of extremely π-acidic catalysts
Carreras, Javier,Gopakumar, Gopinadhanpillai,Gu, Liangu,Gimeno, Ana,Linowski, Pawel,Petu?kova, Jekaterina,Thiel, Walter,Alcarazo, Manuel
, p. 18815 - 18823 (2014/01/06)
Very often ligands are anionic or neutral species. Cationic ones are rare, and, when used, the positively charged groups are normally appended to the periphery of the ligand. Here, we describe a dicationic phosphine with no spacer between the phosphorus atom and the two positively charged groups. This structural feature makes its donor ability poorer than that of phosphites and only comparable to extremely toxic or pyrophoric compounds such as PF 3 or P(CF3)3. By exploiting these properties, a new Au catalyst has been developed displaying a dramatically enhanced capacity to activate π-systems. This has been used to synthesize very sterically hindered and naturally occurring 4,5-disubstituted phenanthrenes. The present approach is expected to be applicable to the development and improvement of many other transition metal catalyzed transformations that benefit from extremely strong π-acceptor ligands. The mechanism of selected catalytic transformations has been explored by density functional calculations.
Aromatic Hydroxylation. Hydroxybenzaldehydes from Bromobenzaldehydes via Reaction of in Situ Generated, Lithiated α-Morpholinobenzyl Alkoxides with Nitrobenzene
Sinhababu, Achintya K.,Borchardt, Ronald T.
, p. 1941 - 1944 (2007/10/02)
A general method for the one-step conversion of bromobenzaldehydes to the corresponding hydroxybenzaldehydes has been developed.The method involves in situ protection of the aldehyde function of the bromobenzaldehyde as its lithium morpholinoalkoxide, followed by lithium-bromine exchange, reaction with nitrobenzene at -75 deg C, and a subsequent acidic workup.The method has been applied to the synthesis of 4,5-dimethoxy-3-hydroxy- (1a), 3,5-dimethoxy-2-hydroxy- (2a), 3,5-bis(benzyloxy)-2-hydroxy- (2b), 3,4-dimethoxy-2-hydroxy- (14), 3-hydroxy-4,5-(methylenedioxy)- (16), and 4,5-dimethoxy-2-hydroxybenzaldehydes (18) from the bromobenzaldehydes 4, 12a, 12b, 13, 15, and 17, respectively.
General Method for the Synthesis of Phthalaldehydic Acids and Phthalides from o-Bromobenzaldehydes via Ortho-Lithiated Aminoalkoxides
Sinhababu, Achintya K.,Borchardt, Ronald T.
, p. 2356 - 2360 (2007/10/02)
A general method for the synthesis of phthalaldehydic acids and phthalides, many of which are key intermediates in natural product synthesis, has been developed. o-Bromobenzaldehydes 1a-f were first protected in situ as α-morpholinoalkoxides by reaction with lithium morpholide.Treatment of the α-morpholinoalkoxides 3a-f with n-butyllithium (to exchange bromine with lithium) followed by sequential treatment with solid CO2 and dilute acid afforded the phthalaldehydic acids 6a-f, respectively.Reduction of 6a-f with NaBH4 in EtOH furnished the phthalides 7a-f, respectively, in nearly quantitative yields.Efficient methods for the synthesis of the o-bromobenzaldehydes 1a-d, which were not readily available, are also described.
