Hydroxyl-Directed Stereoselective Diboration of Alkenes
作者:Thomas P. Blaisdell、Thomas C. Caya、Liang Zhang、Amparo Sanz-Marco、James P. Morken
DOI:10.1021/ja504228p
日期:2014.7.2
An alkoxide-catalyzed directed diboration of alkenyl alcohols is described. This reaction occurs in a stereoselective fashion and is demonstrated with cyclic and acyclichomoallylic and bishomoallylic alcohol substrates. After oxidation, the reaction generates 1,2-diols such that the process represents a method for the stereoselective directed dihydroxylation of alkenes.
Magnetically recyclable Hoveyda-Grubbs catalyst can be readily assembled using magnetic nanoparticles as support, and this catalyst combines convenient recyclability and excellent activity on ring-closing metathesis (RCM) reactions.
Alkenes from Terminal Epoxides Using Lithium 2,2,6,6-Tetramethylpiperidide and Organolithiums or Grignard Reagents
作者:David M. Hodgson、Matthew J. Fleming、Steven J. Stanway
DOI:10.1021/ja045513a
日期:2004.10.1
alkenes, dienes, and allylsilanes) are efficiently prepared by alpha-deprotonation of terminal epoxides using lithium 2,2,6,6-tetramethylpiperidide, followed by in situ trapping with organolithiums or Grignardreagents.
A simple and inexpensive method for the C2 homologation of aldehydes and ketone to 2-alkenals consists of the reaction with allylmagnesium bromide, O-acylation of the resultant 1-alken-4-ol, and ozonolysis.