Intramolecular 1,3-dipolar cycloadditions of dihydroimidazolium ylides: synthesis of pyrrolo[1,2,3-de]quinoxalines and imidazo[1,2-a]indoles
作者:Pedro M. J. Lory、Raymond C. F. Jones、James N. Iley、Simon J. Coles、Michael B. Hursthouse
DOI:10.1039/b605458g
日期:——
an intramolecular 1,3-dipolar cycloaddition reaction that affords (via a reaction cascade involving eliminative ring-opening, recyclisation and prototropic tautomerism) unexpected hexahydropyrrolo[1,2,3-de]quinoxaline products. Steric bulk in both the dihydroimidazole and the dipolarophile allows isolation of an imidazo[1,2-a]indole, the initial product of cycloaddition. When the bromomethyl ketone
Intramolecular Diels−Alder Cycloadditions of Fulvenes. Application to the Kigelinol, Neoamphilectane, and Kempane Skeletons
作者:Bor-Cherng Hong、Fon-Len Chen、Shang-Hung Chen、Ju-Hsiou Liao、Gene-Hsiang Lee
DOI:10.1021/ol047730m
日期:2005.2.1
A variety of polycyclic ring skeletons (e.g., kigelinol, neoamphilectane, and kempene systems) can be prepared rapidly via intramolecularDiels-Alder cycloadditions (IMDA) of fulvenes. The length of the tethers and the diversity of the substituents on the fulvene core dictate the nature of the IMDA pathway. [reaction: see text]
Pyrrolo[1,2,3-de]quinoxalines: unexpected products from 1,3-dipolar cycloaddition of dihydroimidazolium ylides
作者:Raymond C.F Jones、James N Iley、Pedro M.J Lory、Simon C Coles、Mark E Light、Michael B Hursthouse
DOI:10.1016/s0040-4039(01)00617-7
日期:2001.6
4,5-Dihydroimidazoles undergo an N-alkylation and 1,3-dipolar cycloaddition cascade with unsaturated α-bromoketones, with subsequent eliminative ring-opening, recyclisation and tautomerisation to form unexpected hexahydropyrrolo[1,2,3-de]quinoxalines.
4,5-二氢咪唑与不饱和α-溴酮进行N-烷基化和1,3-偶极环加成反应,随后消除开环,环化和互变异构现象,形成意外的六氢吡咯并[1,2,3- de ]喹喔啉。
Asymmetric syntheses of (1R,1′R,5′R,7′R) and (1S,1′R,5′R,7′R)-1-hydroxy-exo-brevicomin and a formal synthesis of (+)-exo-brevicomin
作者:D. Naveen Kumar、B. Venkateswara Rao
DOI:10.1016/j.tetlet.2003.12.157
日期:2004.3
Asymmetric syntheses of (1R,1′R,5′R,7′R) and (1S,1′R,5′R,7′R)-1-hydroxy-exo-brevicomins 1 and 2, volatiles of the male mountainpinebeetle, and a formal synthesis of (+)-exo-brevicomin 3, a component of the attracting pheromone system of several bark beetles have been achieved. The key steps are Birch reduction of commercially available α-picoline, selective Wittig olefination, and Sharpless asymmetric
The development of a new catalytic process: Bu3SnH-catalyzed reductive cyclization of enals and enones
作者:David S Hays、Gregory C Fu
DOI:10.1016/s0040-4020(99)00446-9
日期:1999.7
By sequencing two known reactions, a new catalytic carbon-carbon bond-forming process, the Bu3SnH-catalyzed, PhSiH3-mediated reductive cyclization of enals and enones, has been developed. The addition of EtOH to the reactions leads to reproducibly good yields of the cyclized products; a rationale for including this additive is provided.