Zinc-Catalyzed Allenylations of Aldehydes and Ketones
摘要:
The general zinc-catalyzed allenylation of aldehydes and ketones with an allenyl boronate Is presented. Preliminary mechanistic studies support a kinetically controlled process wherein, after a site-selective Ban exchange to generate a propargyl zinc intermediate, the addition to the electrophile effectively competes with propargyl-allenyl zinc equilibration. The utility of the methodology was demonstrated by application to a rhodium-catalyzed [4 + 2] cycloaddition.
peptide synthesis (SPPS). The robustness of the allenone-mediated peptide bond formation was showcased incisively by the synthesis of carfilzomib, which involved a rare racemization-/epimerization-free N to C peptide elongation strategy. Furthermore, the successful synthesis of the model difficult peptide ACP (65–74) on a solid support suggested that this method was compatible with SPPS. This method combines
Allenone 首次被鉴定为一种高效的肽偶联剂。肽键以α-羰基乙烯基酯为关键中间体形成,其形成和随后的氨解以无外消旋/差向异构化的方式自发进行。丙二烯酮偶联试剂不仅对简单酰胺和二肽的合成有效,而且还适用于肽片段缩合和固相肽合成 (SPPS)。卡非佐米的合成充分展示了丙二烯酮介导的肽键形成的稳健性,该合成涉及一种罕见的无消旋化/差向异构化的 N 到 C 肽延伸策略。此外,在固体支持物上成功合成模型困难肽 ACP (65-74) 表明该方法与 SPPS 兼容。该方法结合了传统活性酯和偶联剂的优点,同时克服了两种策略的缺点。因此,这种丙二烯酮介导的肽键形成策略代表了肽合成的颠覆性创新。
Rapid and Solvent-Free Synthesis of Homoallyl or Homopropargyl Alcohols Mediated by Zinc Powder
作者:Jin-xian Wang、Xuefeng Jia、Tuanjie Meng、Li Xin
DOI:10.1055/s-2005-872178
日期:——
A rapid and efficient procedure for the solvent-free synthesis of homoallylic and homopropargyl alcohols has been achieved by zinc-mediated Barbier-type reaction of carbonyl compounds at room temperature.
Synthesis of homopropargyl alcohols via sonochemical Barbier-type reaction
作者:Adam Shih-Yuan Lee、Shu-Fang Chu、Yu-Ting Chang、Shu-Huei Wang
DOI:10.1016/j.tetlet.2003.12.058
日期:2004.2
were synthesized from the reaction mixture of zinc powder, 1,2-diiodoethane, 3-bromo-1-propyne and aldehyde or ketone in anhydrous THF under ultrasound. The homopropargyl alcohols were obtained as the only product in all cases when aldehydes were reacted with 3-bromo-1-propyne under this sonochemical Barbier-type reaction condition. The homopropargyl alcohol was produced as the major product and the
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
One-Pot, Regioselective Synthesis of Homopropargyl Alcohols using Propargyl Bromide and Carbonyl Compound by the Mg-mediated Reaction under Solvent-free Conditions
in organic synthesis is the most important goal in “Green” chemistry. We report a simple, efficient and facile method for the addition of progargyl bromide to carbonyl compounds using Mg metal as a mediator undersolvent-freeconditions which could regioselectively generate homopropargyl alcohols efficiently in good to excellent yields. The procedure has advantages such as short reaction time, operationally