Le comportement thermique des cetones ethyleniques aliphatiques en fonction du nombre de carbones separant les deux centres insatures, et celui cis-alcoyl-2 acylcyclanes en fonction de la taille du cycle.
New method for generation of β-oxido carbenoid via ligand exchange reaction of sulfoxides: A versatile procedure for one-carbon homologation of carbonyl compounds
one-carbon homologation of carbonylcompounds is described. The method is based on the rearrangement of β-oxido carbenoid which is generated via the ligand exchange reaction of the sulfinyl group of α-chloro β-hydroxy sulfoxide with tert-butyllithium. Addition of the carbanion of aryl 1-chloroalkyl sulfoxides to carbonylcompounds gave the adducts in good yields. The β-oxido carbenoid rearrangement of the
A novel method for generation of carbenoid from α-chloro sulfoxides: A new and versatile procedure for one-carbon homologation of carbonyl compounds to carbonyl compounds having an α-alkyl substituent
Addition of the carbanion of 1-chloroalkyl p-tolyl sulfoxides to carbonylcompound gave the adducts, which were treated with a base followed by t-butyllithium to afford one-carbon homologated carbonylcompounds having an alkyl group at the α-position, via the β-oxido carbenoids, in moderate to good yields.
Selective Homologation of Ketones and Aldehydes with Diazoalkanes Promoted by Organoaluminum Reagents
作者:Keiji Maruoka、Amel B. Concepcion、Hisashi Yamamoto
DOI:10.1055/s-1994-25682
日期:——
Organoaluminum-promoted single homologation or ring expansion of ketones and aldehydes with diazoalkanes has been described, and among various organoaluminum reagents, exceptionally bulky methylaluminum bis(2,6-di-tert-butyl-4-methylphenoxide) (MAD) is found to be highly effective for the selective homologation of various ketones and aldehydes.
The preparation and spectral studies of a series of cyclic β-ketoesters
作者:Sara Jane Rhoads、J.C. Gilbert、A.W. Decora、T.R. Garland、R.J. Spangler、Mary Jane Urbigkit
DOI:10.1016/s0040-4020(01)99237-3
日期:1963.1
their C-methyl derivatives have been prepared and studied in the U.V. and I.R. spectral regions. The enolizable β-ketoesters show a high intensity K band in the 255–263 mμ region associated with the chelated enolic species and two pairs of bands in the 6 μ double bond stretching region which correspond to the structural features of the keto and enol tautomers. The non-enolizable β-ketoesters show only a
Ring Enlargement of<i>α</i>-Ethylidenecycloalkanones to<i>β</i>-Alkylidenecycloalkanones Induced by Trimethylstannyllithium/Aldehyde Equivalents/Lewis Acids
作者:Jun Fujiwara、Jin Tokuyasu、Tadashi Sato
DOI:10.1246/bcsj.68.289
日期:1995.1
α-Ethylidenecycloalkanones underwent a ring enlargement to β-alkylidenecycloalkanones upon a treatment with trimethylstannyllithium/aldehyde equivalents/Lewis acids with high stereoselectivity.