Easy oxidation of organozinc compounds to alcohols
摘要:
Primary and secondary organozine compounds can be readily oxidized by dry air (slow absorption) in THF to give, without any reductive workup, primary and secondary alcohols in good to excellent yields.
An efficient preparation of N-methyl-O-tert-butylhydroxylamine hydrochloride has been settled, which allowed the synthesis of modified Weinreb amides. Nucleophilic addition of organolithium and Grignard reagents on these N-tert-butoxy-N-methylamides afforded efficiently the corresponding ketones and reduction with DIBAL furnished the corresponding aldehydes in good yields up to 97%.
Cycloadditions of 3-methoxyfuran (1) with several mono-activateddienophiles gave the endo adducts stereoselectively under the usual conditions in satisfactory yields; two of the adducts were transformed into potential intermediates (7a) and (7b) for the synthesis of (±)-avenaciolide and (±)-isoavenaciolide, respectively.
Soluble, highly conjugated derivatives of polyacetylene from the ring-opening metathesis polymerization of monosubstituted cyclooctatetraenes: synthesis and the relationship between polymer structure and physical properties
作者:Christopher B. Gorman、Eric J. Ginsburg、Robert H. Grubbs
DOI:10.1021/ja00057a024
日期:1993.2
Abstract : Using well-defined tungsten-based olefinmetathesis catalysts, a family of partially substituted polyacetylenes have been synthesized via the ring-opening metathesis polymerization (ROMP) of monosubstituted cyclooctatetraenes (RCOT). These polymers are highly conjugated as evidenced by their visible absorption maxima, they are of high molecular weight as evidenced by gel permeation chromatography
Photochemical reactions of chromium-alkoxycarbene complexes with stabilized ylides to produce push-pull captodative allenes
作者:Michael R. Sestrick、Michael Miller、Louis S. Hegedus
DOI:10.1021/ja00037a008
日期:1992.5
Photolysis of chromium alkoxycarbene complexes in the presence of stabilized ylides produced allenes having effect withdrawing groups on C-1 and electron donating groups on C-3. These highly reactive captodative allenes rearranged to 1,3-substituted-1,3-dienes under mildly acidic conditions and hydrolyzed to γ-ket-α,β-unsaturated esters, both in excellent yield
Synthesis of<i>anti</i>-1,3-Diols through RuCl<sub>3</sub>/PPh<sub>3</sub>-Mediated Hydrogenation of β-Hydroxy Ketones: An Alternative to Organoboron Reagents
Hydrogenation of enantioenriched β-hydroxyketones promoted by the catalyst generated in situ from commercially available and inexpensive RuCl3 and PPh3 under hydrogen pressure allowed the efficient preparation of a variety of anti-1,3-diols in good yields and with a high level of diastereoselectivity. This method should be an interesting alternative to organoboronreagents for the diastereoselective