Geminal Acylation with Methyl-Substituted Analogues of 1,2-Bis[(trimethylsilyl)oxy]cyclobutene
作者:Sheldon N. Crane、Tracy J. Jenkins、D. Jean Burnell
DOI:10.1021/jo971055v
日期:1997.12.1
BF3 . Et2O-catalyzed geminal acylation of ketones and acetals with 3-methyl-1,2-bis[(trimethylsilyl)oxy)]cyclobutene (3) provided methylcyclopentanediones in yields that ranged from 40 to 94%. The best substrates were unhindered cyclohexanones. With acetals, stereochemical preferences in the initial Mukaiyama-like aldol step giving cyclobutanones translated into the stereochemistry of the ultimate cyclopentanedione products. With ketones, equilibration of the initial cyclobutanone compounds resulted in cyclopentanedione products with a different stereochemical preference. The gem-dimethylcyclobutene reagent 4 reacted with ketones to give gem-dimethylcyclopentanediones in modest yield. The process was much more stereochemically efficient than the reaction with 3. Rearrangement from the initial cyclobutanone compound was partially diverted toward air-sensitive 3-furanone compounds and ring-opened 1,2-diones. Only furanones (e.g., 52 and 53) were isolated from reactions with the tetramethylcyclobutene 51.
The BF<sub>3</sub>·Et<sub>2</sub>O-Catalyzed Reaction of 1,2-Bis[(trimethylsilyl)oxy]cyclobutene and Analogues with Aromatic Ketones
作者:Sheldon N. Crane、D. Jean Burnell
DOI:10.1021/jo971867r
日期:1998.2.1
HEINE, H. -C.;HARTMANN, W.;KNOPS, H. -J.;PRIESNITZ, U., TETRAHEDRON LETT., 1983, 24, N 26, 2635-2638
作者:HEINE, H. -C.、HARTMANN, W.、KNOPS, H. -J.、PRIESNITZ, U.
DOI:——
日期:——
SALAUN, JACQUES;KARKOUR, BELKACEM, TETRAHEDRON LETT., 28,(1987) N 40, 4669-4672
作者:SALAUN, JACQUES、KARKOUR, BELKACEM
DOI:——
日期:——
Heine,H.-G.; Wendisch,D., Justus Liebigs Annalen der Chemie, 1976, p. 463 - 475