91164-84-0Relevant academic research and scientific papers
Relay Catalysis to Synthesize β-Substituted Enones: Organocatalytic Substitution of Vinylogous Esters and Amides with Organoboronates
Sundstrom, Sasha,Nguyen, Thien S.,May, Jeremy A.
supporting information, p. 1355 - 1359 (2020/02/13)
Organocatalysis was shown to facilitate conjugate additions to vinylogous esters and amides for the first time. Subsequent elimination of a β-alcohol or amine provided π-conjugated β-substituted enones. Remarkably, nucleophile addition to the electron-rich vinylogous substrates is more rapid than classical enones, forming monosubstituted products. A doubly organocatalytic (organic diol and methyl aniline) conjugate addition synthesized the products directly from alkynyl ketones. Both of these catalytic transformations are orthogonal to transition metal catalysis, allowing for good yields, easily accessible or commercially available reagents, high selectivity, reagent recovery and recyclability, facile scalability, and exceptional functional group tolerance.
Organocatalytic Enantioselective Conjugate Alkynylation of β-Aminoenones: Access to Chiral β-Alkynyl-β-Amino Carbonyl Derivatives
Mao, Bin,Meng, Xin,Wang, Jian-Fei,Yu, Chuan-Ming,Zhang, Chao-Huan
supporting information, p. 7427 - 7432 (2020/10/09)
Readily available potassium alkynyltrifluoroborates were used for organocatalytic asymmetric conjugate alkynylation of β-enaminones. The interception of a modified binaphthol catalyst and in situ generated organodifluoroboranes proved important to access functionalized β-alkynyl-β-amino carbonyls and derivatives with improved chemo-reactivity and enantio-induction. Mechanistic studies revealed the impact of molecular sieves on efficiency and stereocontrol. The products undergo additional functionalization to yield a diverse set of valuable β-alkynyl-β-amino carbonyl scaffolds.
Novel Bicycloannulation via Tandem Vinylation and Intramolecular Diels-Alder Reaction of Five-Membered Heterocycles: A New Approach to Construction of Psoralen and Azapsoralen
Hayakawa, Kenji,Yodo, Mitsuaki,Ohsuki, Satoru,Kanematsu, Ken
, p. 6735 - 6740 (2007/10/02)
trans-4-(Phenylsulfinyl)-3-buten-2-one (1) was found to undergo a new versatile addition-elimination reaction with five-membered compounds such as furans, pyrroles, imidazole, pyrazole, and 6-(dimethylamino)fulvene to give an excellent yield of the corresponding trans-4-aryl-3-buten-2-ones (3).The thermal reaction of the propargyl ethers 7a,b prepared from 3a,b gave a single intramolecular Diels-Alder adduct, 8a,b, in 59percent and 38percent yields, respectively.Treatment of 7a,b with t-BuOK in refluxing tert-butyl alcohol afforded another type of Diels-Alder adduct, 10a,b, in almost quantitative yields.This bicycloannulation strategy was applied to a new synthesis of psoralen which is of current interest due to its unique photoreactivity with DNA.The acid-catalyzed reaction of sulfoxide 12, prepared from ethyl acatoacetate in high yield, with furan gave 13 in 78percent yield.The intramolecular Diels-Alder reaction of the neopentyl acetal of 13 in the presence of Pd/C followed by acid hydrolysis afforded the tricyclic ketone 18 in 38percent yield.Baeyer-Villiger oxidation and dehydrogenation of 18 completed the synthesis of psoralen (11).Furthermore, hitherto unknown azapsoralen 20 was also synthesized by this method.
