?-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
Diastereotopic Group Selection in Hydroxy‐Directed Intramolecular CH Alkenylation of Indole under Oxidative Palladium(II) Catalysis
作者:Sandeep R. Kandukuri、Lin‐Yu Jiao、Axel B. Machotta、Martin Oestreich
DOI:10.1002/adsc.201301108
日期:2014.5.5
intermolecular hydroxy‐directed CH bond alkenylations. No asymmetric induction was obtained with chiral ligands, mono‐N‐protected amino acids (MPAAs) in particular. Conversely, the cyclization of indole‐derived precursors was substantially more efficient, and installation of a substituent in the benzylic position rendered these intramolecular CH bond alkenylations diastereoselective. The diastereotopic
ALLYLATION OF ESTERS PROMOTED BY METALLIC DYSPROSIUM IN THE PRESENCE OF MERCURIC CHLORIDE
作者:Yu Jia、Mingfu Zhang、Fenggang Tao、Jingyao Zhou
DOI:10.1081/scc-120006467
日期:2002.1
ABSTRACT In the presence of mercuric chloride, the reactions of esters with allyl bromide and metallic dysprosium in anhydrous THF give diallyl alkyl carbinols in good yields. When γ-butyrolactone is used as the substrate, the corresponding product is 4-allyl-6-heptene-1, 4-diol.
Palladium-Catalyzed Cyclizations of 1,6-Dienes in the Presence of Lewis Acids
作者:Chang Ho Oh、Jung Duk Kim、Je Wook Han
DOI:10.1246/cl.2001.1290
日期:2001.12
Palladium-catalyzed cyclizations of several 1,6-dienes were accomplished by utilizing a catalytic amount of additives. Use of Lewis acids gave the endocyclic compounds, while use of silver(I) salts gave the exocyclic compounds.
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.