1283669-08-8Relevant academic research and scientific papers
Ag2O nanoparticle-catalyzed substrate-controlled regioselectivities: direct access to 3-ylidenephthalides and isocoumarins
Chaudhary, Sandeep,Shyamlal, Bharti Rajesh K.,Yadav, Lalit,Tiwari, Mohit K.,Kumar, Krishan
, p. 23152 - 23162 (2018/07/10)
Herein, we disclose the first example of an efficient, silver oxide nanoparticle-catalyzed, direct regioselective synthesis of 3-ylidenephthalides 11-16 and isocoumarins 17-20via sonogashira type coupling followed by substrate-controlled 5-exo-dig or 6-endo-dig cyclization reaction, respectively. This one pot coupling involves reaction of substituted 2-halobenzoic acid with meta/para-substituted and ortho-substituted terminal alkynes, which proceeded in a regioselective manner resulting in the formation of 3-ylidenephthalides or isocoumarins, respectively, in excellent yields (up to 95%) with complete Z-selectivity. This protocol features relatively broad substrate scope, mild conditions, operational simplicity, and is favourable with aromatic/alicyclic terminal alkynes. The competition experiments and gram-scale synthesis further highlight the importance and versatility of the methodology. The proposed mechanistic pathways illustrate that the regioselectivity is substantially being controlled by the substituent(s) present on the acetylenic phenyl ring.
New method for the synthesis of lactones via nickel-catalyzed isocyanides insertion
Fei, Xiang-Dong,Tang, Ting,Ge, Zhi-Yuan,Zhu, Yong-Ming
, p. 3262 - 3271 (2013/10/01)
A novel nickel catalyst for the reaction of tert-butyl isocyanide insertion was discovered. In this approach, 1,2-bis(diphenylphosphino)ethane (L3) serves as an efficient ligand, thereby allowing the preparation of lactones from (o-bromophenyl)phenylethanone derivatives. It is noteworthy that this is the first example of nickel acting as a metal catalyst in the reactions of tert-butyl isocyanide insertion. The significance of this methodology may draw many chemists attention in the field of isocyanide-incorporating reactions. [Supplementary materials are available for this article. Go to the publisher's online edition of Synthetic Communications for the following free supplemental resource(s): Full experimental and spectral details.]
Palladium-catalyzed synthesis of isocoumarins and phthalides via tert -butyl isocyanide insertion
Fei, Xiang-Dong,Ge, Zhi-Yuan,Tang, Ting,Zhu, Yong-Ming,Ji, Shun-Jun
, p. 10321 - 10328 (2013/01/15)
A novel and highly efficient strategy for the synthesis of isocoumarins and phthalides through a palladium(0)-catalyzed reaction incorporating tert-butyl isocyanide has been developed. This process, providing one of the simplest methods for the synthesis of this class of valuable lactones, involves two steps including cyclization reaction and simple acid hydrolysis. The methodology is tolerant of a wide range of substrates and applicable to library synthesis.
NHC-catalyzed oxidative cyclization reactions of 2-alkynylbenzaldehydes under aerobic conditions: Synthesis of O-Heterocycles
Park, Jong Hyub,Bhilare, Sachin V.,Youn, So Won
, p. 2228 - 2231 (2011/07/09)
Chemical equations presented. An NHC-catalyzed, regio- and stereoselective oxidative cyclization of o-alkynylbenzaldehydes bearing an unactivated alkyne moiety as an internal electrophile has been developed to afford phthalides and isocoumarins. A single organocatalytic system enabled two sequential C-O bond formations to take place in an atom economical manner via highly efficient dual activation. Molecular oxygen in air could be utilized as a source of an oxygen atom for the oxidation of aldehydes to the corresponding benzoic acids under our newly developed reagent system.
