Organometallic-type reactions in aqueous media mediated by indium. Allylation of acyloyl-imidazoles and pyrazoles. Regioselective synthesis of β,γ-unsaturated ketones
作者:Vernal J. Bryan、Tak-Hang Chan
DOI:10.1016/s0040-4039(97)01512-8
日期:1997.9
Indiummediated coupling of allylic bromide with acyloyl-imidazoles or pyrazoles in aqueousmedia gives the corresponding tertiary alcohols or ketones in good yield. The reaction provides a facile regioselective synthesis of β,γ-unsaturated ketones and its usefulness is demonstrated by the synthesis of the monoterpene artemesia ketone.
?-Cleavage of Bis(homoallylic) Potassium Alkoxides. Two-Step Preparation of Propenyl Ketones from Carboxylic Esters. Synthesis ofar-Turmerone, ?-Damascone, ?-Damascone, and ?-Damascenone
作者:Roger L. Snowden、Simon M. Linder、Bernard L. Muller、Karl H. Schulte-Elte
DOI:10.1002/hlca.19870700721
日期:1987.11.4
The transformation of 36 bis(homoallylic) alcohols VII to alkenones IX and Xvia β-cleavage of their potassiumalkoxides VIIa in HMPA has been investigated (cf. Scheme 2). These studies have established an order of β-cleavage for 2-propenyl, 1-methyl-2propenyl, 2-methyl-2-propenyl, 1,1-dimethyl-2propenyl, and benzyl groups in alkoxides 49a–56a and have allowed a comparison between the β-cleavege reaction
Fragmentation of homoallylic alkoxides. Synthesis of propenyl and 2-methylpropenyl ketones from carboxylic esters
作者:Roger L. Snowden、Bernard L. Muller、Karl H. Schulte-Elte
DOI:10.1016/s0040-4039(00)86824-0
日期:1982.1
An efficient two-step synthesis of propenyl and 2-methylpropenyl ketonesfromcarboxylic esters is described which uses as the key step the fragmentation of a potassium dihomoallylic alkoxide under mild thermolytic conditions.
First and second generation Grubbs' catalyst mediate under otherwise identical conditions two different cyclization modes with high selectivity: a ring-closingmetathesis and an atom-transfer radical addition (ATRA) pathway.
Etude de la régiosélectivité de l'action des organozinciques sur les α-iminoesters: synthèse d'α-aminoesters C-substitués par un groupe α-insaturé ou α-fonctionnel
作者:G. Courtois、L. Miginiac
DOI:10.1016/0022-328x(89)85133-2
日期:1989.11
Organozinc compounds prepared from allylic or propargylicbromides, and from α-bromoesters or α-bromoamides react regiospecifically with α-iminoesters R′NCHCOOR″ (R′,R″ = primary, secondary or tertiary alkyl group) to give α-aminoesters R′NHCH(R)COOR″ in good yields.