Formation of cyclic carbonates in the reaction of 1,2-ditertiary diols with acetic anhydride and 4-(dimethylamino)pyridine
作者:Vidya Bhushan、Tushar K. Chakraborty、Srinivasan Chandrasekaran
DOI:10.1021/jo00195a019
日期:1984.10
Acetoacetylation with 2,2,6-trimethyl-4H-1,3-dioxin-4-one: a convenient alternative to diketene
作者:Robert J. Clemens、John A. Hyatt
DOI:10.1021/jo00214a006
日期:1985.7
Cobalt(II) chloride catalyzed acylation of alcohols with acetic anhydride: scope and mechanism
作者:Javed Iqbal、Rajiv Ranjan Srivastava
DOI:10.1021/jo00033a020
日期:1992.3
Cobalt(II) chloride catalyzes the acetylation of a variety of alcohols with acetic anhydride in excellent yield. Primary hydroxyl groups can be selectively acylated in the presence of secondary and tertiary ones while the secondary hydroxyl groups can be preferentially acetylated in the presence of tertiary ones. Tertiary alcohols have been found to give ketones, acetoacetates, olefins, and diketene in addition to the acetate. The beta-hydroxy esters and ketones can be acylated under these conditions without any elimination, and this reaction has been compared with 4-(dimethylamino)pyridine (DMAP)-mediated acylations where elimination of the resulting beta-acetoxy carbonyl compound is observed. A detailed investigation of the acylation of tertiary alcohols has revealed that these reactions proceed via a tertiary alkoxy radical and ketene. A mechanism for these acylations is proposed by invoking an electron-transfer process.
Transacetoacetylation with tert-butyl acetoacetate: synthetic applications
作者:J. Stewart Witzeman、W. Dell Nottingham
DOI:10.1021/jo00005a013
日期:1991.3
Reaction of various nucleophiles with tert-butyl acetoacetate (t-BAA, 1a) is shown to be a convenient method for the preparation of a wide variety of acetoacetic acid derivatives. This material can be used to prepare acetoacetates and acetoacetamides from a wide variety of alcohols and amines. Reaction of 1a with an unhindered primary amine such as n-heptylamine under standard conditions gives unwanted byproducts due to the formation of the enamines 24 and 25. Formation of these byproducts can be minimized by dilution and/or altering the mode of addition.
The transacetoacetylation: Mechanistic implications.