Design and Synthesis of Angularly Annulated Spirocyclics via Enyne Metathesis and the Diels–Alder Reaction as Key Steps
作者:Sambasivarao Kotha、Rashid Ali、Arti Tiwari
DOI:10.1055/s-0034-1378280
日期:——
developed a simple and an efficient route to a range of angularly fused spirocycles by the application of enynemetathesis and the Diels–Alderreaction as keysteps. The enynemetathesis protocol has been further extended to the dibenzylation of indane-1,3-dione by using cross-enyne metathesis in the presence of hexa-1,5-diene with the aid of Grubbs’ 1st generation catalyst followed by an aromatization
A synthesis of symmetrical gem-difluoromethylenated angular triquinanes is described. The synthetic strategy involved sequential fluoride-catalyzed nucleophilic addition of PhSCF2SiMe3 (1) to 2,2-diallylated or 2,2-dipropargylated indane-1,3-diones 2 followed by stereoselective radical cyclization of the resulting adducts 3 to provide the cyclized gem-difluoromethylenated diquinanes 4 as a mixture
Solvent-Controlled Highly Selective Bis- and Monoallylation of Active Methylene Compounds by Allyl Acetate with Palladium(0) Nanoparticle
作者:Brindaban C. Ranu、Kalicharan Chattopadhyay、Laksmikanta Adak
DOI:10.1021/ol702099v
日期:2007.10.1
catalyst for the allylation of active methylene compounds. Very efficient bisallylation is achieved for a variety of active methylene compounds by allyl acetate and itsderivatives in one stroke in THF solvent. The reaction in water provides monoallylated product selectively by allyl acetate only. The recovered Pd(0) nanoparticle is recycled. A probable mechanism is suggested.
tion of 1,3-diketones and methyl acetoacetate gave exo-methylenecyclopentanes in moderate to good yields with high isomer selectivity. The double allylation step effectively proceeded in the presence of a Ru(II) precatalyst, [Cp*RuCl(cod)], in 1,2-dichloroethane at 90 degrees C. The subsequent cycloisomerization was carried out upon addition of triethylsilane as a hydride source without purification
Sequential Reactions of Trimethylsilyldiazomethane with 4-Alkenyl Ketones and Aldehydes Catalyzed by Lewis Bases
作者:Huaqing Liu、Matthew J. O’Connor、Chunrui Sun、Donald J. Wink、Daesung Lee
DOI:10.1021/ol401124t
日期:2013.6.21
A sequence of a carbonyl addition between 4-alkenyl ketones and aldehydes with trimethylsilyldiazomethane followed by a 1,3-Brook rearrangement and an intramolecular 1,3-dipolar cycloaddition was promoted by Lewis bases tetrabutylammonium triphenyldifluorosilicate (TBAT) or potassium tert-butoxide (KO-t-Bu). Through these concatenated bond-forming processes, a variety of novel bi- and tricyclic Δ1-pyrazolines