Application of elementoorganic compounds of 15th and 16th Groups in organic synthesis. 100. Reactions of carbonyl compounds with [(trimethylsilyl)propargyl]diisobutyltelluronium bromide mediated by different strong bases: highly regioselective synthesis of (trimethylsilyl)propargyl alcohols and highly stereoselective synthesis of cis-(trimethylsilyl)alkynyl epoxides
摘要:
[(Trimethylsilyl)propargyl)]diisobutyltelluronium bromide (1), after being treated with alkyl- or aryllithium reagent, undergoes a lithium-tellurium exchange reaction via an unstable transient tetraorganyltellurium intermediate, and the in situ generated lithium species reacts with carbonyl compounds to give (trimethylsilyl)propargyl alcohols 2 in high yields with high regioselectivity. However, when the telluronium salt 1 was treated with nonnucleophilic bases such as LDA or lithium 2,2,6,6-tetramethylpiperidide, the moderately stabilized silylated telluronium ylide formed. The silylated telluronium ylide reacted with carbonyl compounds to afford (trimethylsilyl) alkynyl epoxides 11 in good to excellent yields with high cis stereoselectivity.
The propargyltitanium reagents derived from 1-alkylpropyne condensed with aldehydes to give α-allenyl alcohol regioselectively, while the allenyltitanium reagents generated from 1-alky1-1-butyne derivatives gave threo-β-acetylenic alcohols with high regio- and stereoselectivities. The course of the reaction was determined by the substitution pattern of starting alkynes. The similar reactions of metallated
Regioselective Addition Reactions of Propargyl Bromides to Carbonyl Compounds with Gallium Catalyzed by Indium
作者:Phil Ho Lee、Hyun Kim、Kooyeon Lee
DOI:10.1002/adsc.200505046
日期:2005.7
propargyl bromides having substituents at the γ-position and gallium in the presence of 5 mol % of indium with aldehydes and ketones selectively produced homoallenyl alcohols in good to excellent yields. Treatment of organogallium reagents obtained from propargyl bromide or propargyl bromides having substituents at the α-position and gallium in the presence of 5 mol % of indium with carbonyl compounds selectively
A CONVENIENT SYNTHESIS OF α-HYDROXYALLENES BY THE REACTION OF PROPARGYL IODIDES WITH ALDEHYDES IN THE PRESENCE OF STANNOUS HALIDE
作者:Teruaki Mukaiyama、Taira Harada
DOI:10.1246/cl.1981.621
日期:1981.5.5
In the presence of stannous halide, propargyl iodides react with aldehydes in an aprotic solvent to yield α-hydroxyallenes as major products, particularly in the cases of γ-substituted propargyl iodides, along with β-hydroxyacetylenes.
REACTION OF PROPARGYL BROMIDE AND TRIMETHYLSILYLPROPARGYL IODIDE WITH METALLIC TIN, ALUMINUM, AND ALDEHYDES OR KETONES. SELECTIVE SYNTHESIS OF β-ACETYLENE, β-TRIMETHYLSILYLACETYLENE, AND α-TRIMETHYLSILYLALLENE ALCOHOLS
β-Acetylenic and α-allenic alcohols were synthesized selectively by the reaction of aldehydes and ketones with organotin compounds prepared by treatment of propargyl bromide or trimethylsilylpropargyl iodide with metallic tin and aluminum in a suitable solvent.
obtained by the reaction of 3-bromo-1-butyne (11) with tributylstibine. The corresponding stiborane (13) reacted with aldehyde to give acetylenic alcohol (14) exclusively in good yield, and the diastereoselectivity was moderately in favour of the threo isomer in the presence of MgBr2. All of the reactions had good chemoselectivity for aldehyde.