Nucleophilic Cycloaromatization of Ynamide-Terminated Enediynes
作者:Andrei Poloukhtine、Valentin Rassadin、Alexander Kuzmin、Vladimir V. Popik
DOI:10.1021/jo101238x
日期:2010.9.3
ynamide fragment. The resulting ketenimmonium cation then cyclizes to produce naphthyl cation, which rapidly reacts with nucleophiles or undergoes Friedel−Crafts addition to aromatic compounds. In alcohols, addition of the nucleophilic solvent across the activated triple bond competes with the cyclization reaction. The ratio of cyclized to solvolysisproducts decreases with the increase in ring size.
Synthesis of Small and Large Fused Bicyclic Compounds by Tandem Dienyne Ring-Closing Metathesis
作者:Hyeon Park、You-Lee Hong、Yongjoo B. Kim、Tae-Lim Choi
DOI:10.1021/ol101233k
日期:2010.8.6
A tandem ring-closing metathesis reaction using ruthenium catalyst was carried out to synthesize various fused bicyclic compounds containing both small and large rings. Fast ring-closure of the small ring and slow ring-closure of the large ring resulted in the formation of only one Isomer. Further manipulation such as the Diels-Alder reaction was carried out to prepare a complex molecule containing multiple rings of different sizes.
Direct Synthesis of α-Amino Nitriles from Sulfonamides via Base-Mediated C–H Cyanation
Herein, we disclose a transition-metal-free reaction system that enables α-cyanation of sulfonamides through C–H bond cleavage for the preparation of α-amino nitriles, including difficult-to-access all-alkyl α-tertiary scaffolds. More than 50 substrate examples prove a wide functional group tolerance. Additionally, its synthetic practicality is highlighted by gram-scalability and the late-stage modification