Cobalt(II)-Catalyzed Conversion of Allylic Alcohols/Acetates to Allylic Amides in the Presence of Nitriles
摘要:
Various secondary allylic alcohols or their acetates and tertiary allylic alcohols can be converted to the corresponding transposed allylic amides in the presence of a catalytic quantity of cobalt(II) chloride and acetic anhydride in acetonitrile. Tertiary alcohols undergo complete rearrangement whereas secondary ones afford a mixture of regioisomers. Moderate yields of amides are also obtained by reacting acrylonitrile with secondary alcohols in 1,2-dichloroethane. The presence of acetic anhydride or acetic acid is crucial to the formation of amides as the absence of the former affords no amides and the allylic alcohols are mainly recovered as regioisomeric mixtures. The regioselectivity during amide formation can be enhanced by using cobalt complexes 14-16 in acetic acid medium. Some preliminary studies indicate that these reactions are proceeding via an pi-allyl complex or tight ion pair rather than a [3,3] sigmatropic rearrangement of acetamidate obtained in a Pinner reaction.
Arene-catalysed reductive desulfonylation and desulfinylation reactions: New routes for alkyllithiums
作者:Emma Alonso、David Guijarro、Miguel Yus
DOI:10.1016/0040-4020(94)01116-h
日期:1995.2
The reaction of alkyl phenylsulfones (1) with an excess of lithium powder and a catalytic amount of naphthalene (8 mol %) in the presence of a carbonyl compound or chlorotrimethylsilane (Barbier-type conditions) in THF at temperatures ranging between −78 and 20°C leads, after hydrolysis, to the expected products (2) arising from the corresponding alkyllithium generated in situ. When the same methodology
Exploration of the diastereoselectivity in an unusual Grignard reaction and its application towards the synthesis of styryl lactones 7-epi-(+)-goniodiol and 8-epi-(−)-goniodiol
作者:Subhash P. Chavan、Harshali S. Khatod、Tamal Das、Kumar Vanka
DOI:10.1039/c6ra03192g
日期:——
chain secondary alcohols possessing a terminal olefin, which are synthetically important intermediates. As an application of this method, the diastereoselective synthesis of styryl lactones viz. 7-epi-(+)-goniodiol (29) and 8-epi-(−)-goniodiol (30) has been achieved.
Marcou,A.; Normant,H., Bulletin de la Societe Chimique de France, 1965, p. 3491 - 3494
作者:Marcou,A.、Normant,H.
DOI:——
日期:——
Palladium(II)-catalyzed carbonylation of 3-buten-1-ols and 3-butyn-1-ols: an efficient synthesis of .gamma.-butyrolactones
作者:Yoshinao Tamaru、Makoto Hojo、Zenichi Yoshida
DOI:10.1021/jo00003a036
日期:1991.2
Palladium(II)-catalyzed dicarbonylation of 3-buten-1-ols (1) in the presence of propylene oxide and ethyl orthoacetate in methanol-dichloromethane under carbon monoxide at atmospheric pressure afforded alpha-[(methoxycarbonyl)methyl]-gamma-butyrolactones (2) in good yields. This dicarbonylation reaction occurs via stereospecific cis addition. Under similar conditions, 4-(trimethylsilyl)-3-butyn-1-ols (4a and 4b) undergo dicarbonylation to provide cis-dicarbonylated alpha-methylene-gamma-butyrolactones (5a and 5b, respectively). 4-Alkyl-and 4-aryl-3-butyn-1-ols (4c-g), on the other hand, undergo trans alkoxycarbonylation across the triple bond and selectively furnish E tetrasubstituted alpha-methylene-gamma-butyrolactones (6).
Photosensitized cis/trans isomerization of 1-(1-propenyl)cycloalkenes
作者:Wayne D. Inman、Kenneth A. J. Sanchez、Manuel A. Chaidez、Donald R. Paulson