55759-12-1Relevant articles and documents
Sustainable Palladium-Catalyzed Tsuji-Trost Reactions Enabled by Aqueous Micellar Catalysis
Braga, Felipe C.,Gallou, Fabrice,Lee, Nicholas R.,Lippincott, Daniel J.,Lipshutz, Bruce H.,Moghadam, Farbod A.,Zhu, Bingchun
supporting information, (2020/07/15)
Palladium-catalyzed allylic substitution, or "Tsuji-Trost"reactions, can be run under micellar catalysis conditions featuring not only chemistry in water but also numerous combinations of reaction partners that require low levels of palladium, typically on the order of 1000 ppm (0.1 mol %). These couplings are further characterized by especially mild conditions, leading to a number of cases not previously reported in an aqueous micellar medium. Inclusion of diverse nucleophiles, such as N-H heterocycles, alcohols, dicarbonyl compounds, and sulfonamides is described. Intramolecular cyclizations further illustrate the broad utility of this process. In addition to recycling studies, a multigram scale example is reported, indicative of the prospects for scale up.
Access to oxetane-containing psico-nucleosides from 2-methyleneoxetanes: A role for neighboring group participation?
Liang, Yanke,Hnatiuk, Nathan,Rowley, John M.,Whiting, Bryan T.,Coates, Geoffrey W.,Rablen, Paul R.,Morton, Martha,Howell, Amy R.
experimental part, p. 9962 - 9974 (2012/02/05)
The first psico-oxetanocin analogue of the powerful antiviral natural product, oxetanocin A, has been readily synthesized from cis-2-butene-1,4-diol. Key 2-methyleneoxetane precursors were derived from β-lactones prepared by the carbonylation of epoxides. F+-mediated nucleobase incorporation provided the corresponding nucleosides in good yield but with low diastereoselectivity. Surprisingly, attempted exploitation of anchimeric assistance to increase the selectivity was not fruitful. A range of 2-methyleneoxetane and related 2-methylenetetrahydrofuran substrates was prepared to explore the basis for this. With one exception, these substrates also showed little stereoselectivity in nucleobase incorporation. Computational studies were undertaken to examine if neighboring group participation involving fused [4.2.0] or [4.3.0] intermediates is favorable (Figure presented).
A novel pentose synthesis via palladium(II)-catalyzed cyclization of an unstable hemiacetal
Awasaguchi, Ken-Ichiro,Miyazawa, Masahiro,Uoya, Ikuyo,Inoue, Koichi,Nakamura, Koji,Yokoyama, Hajime,Hirai, Yoshiro
experimental part, p. 2105 - 2121 (2011/04/24)
PdCl2(PhCN)2 (5 mol%)-catalyzed cyclization of a hemiacetal derived from (E,2S,3R)-2,3-isopropylidenedioxy-6-(tetrahydro-2H- pyran-2-yl)-4-hexenal and methanol gave substituted furanoside in moderate yield, exclusively via 5-exo-mode cyclization, without the need for a reoxidant. New stereogenic centers at C1 and C4 on the tetrahydrofuran ring showed preferential 1R and 4R stereochemistry due to anomeric effect (n oσ*c-o) and A1,2 strain, respectively. This methodology was applied to stereocontrolled synthesis of pentoses: D-ribose and L-lyxose. The Japan Institute of Heterocyclic Chemistry.
