Alkylation of 2-Butyl-4,4-dimethyl-4H-benzo[d][1,3]oxathiine-1,1-dioxide, a New Class of Acyl Anion Equivalents as an Alternative to Dithianes
作者:Robert K. Boeckman、Susan M. Hanson、Jeremy A. Cody
DOI:10.3987/com-06-s(w)56
日期:——
,3]oxathiine-1,1-dioxide has been found to react with several electrophiles, such as various halides and aldehydes, upon regioselective deprotonation. This method utilizes the sulfone group to form new carbon-carbon bonds while serving as a masked carbonyl. Subsequent hydrolysis of the sulfone provides a facile approach toward many useful synthetic intermediates. This methodology could provide a useful
?-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
A reaction mixture of β,γ-unsaturatedketone and BF 3 .OEt 2 in CH 3 OH was stirred at room temperature and β-methoxy ketone was produced in high yield. The β-amino ketone was obtained as the major product from a reaction mixture of β,γ-unsaturatedketone, AlCl 3 and Ts-NH 2 in CH 2 Cl 2 at room temperature. This Lewis acid promoted β-substitution reaction mechanism was proposed as that the process
InBr<sub>3</sub>-Catalyzed Alkynylation and Allylation of Acid Chlorides: A Facile Synthesis of Alkynyl and Allyl Ketones
作者:J. S. Yadav、B. V. Reddy、M. Sridhar Reddy、G. Parimala
DOI:10.1055/s-2003-42438
日期:——
Alkynylsilanes and allyltrimethylsilane undergo smooth coupling with acid chlorides in the presence of 5 mol% of indium tribromide under mild conditions to afford the corresponding α,β-acetylenic ketones and β,γ-unsaturated ketones in excellent yields in a short reaction time with high selectivity.
TMG-promoted [3 + 2] organocatalytic 1,3-dipolarcycloaddition reactions of allyl ketones with in situ generated nitrileoxides have been developed. This strategy could generate 3,5-disubstituted isoxazolines in high yields and regioselectivities.