Regioselective propargylation of aldehydes using potassium allenyltrifluoroborate promoted by tonsil
摘要:
The propargylation of aldehydes using potassium allenyltrifluoroborate promoted by tonsil, an inexpensive and readily available clay, in a chemo- and regioselective way is described. The method is simple and avoids the use of air and moisture sensitive organometallics and products were obtained in good to moderate yields. (C) 2016 Elsevier Ltd. All rights reserved.
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。
Efficient method for propargylation of aldehydes promoted by allenylboron compounds under microwave irradiation
作者:Jucleiton J R Freitas、Queila P S B Freitas、Silvia R C P Andrade、Juliano C R Freitas、Roberta A Oliveira、Paulo H Menezes
DOI:10.3762/bjoc.16.19
日期:——
The propargylation of aldehydes promoted by microwaveirradiation using allenylboron compounds in a chemo- and regioselective way is described. The corresponding products were obtained in short reaction time, high yield and purity without the need of any solvent when allenylboronic acid pinacol ester was used, or using a minimal amount of acetone when potassium allenyltrifluoroborate was used.
quite scarce. We describe an extremely mild and selective method for either the propargylation or allenylation of carbonyl compounds catalyzed by the abundant, safe, and inexpensive metal titanium. These reactions can selectively provide homopropargylic alcohols from aldehydes and ketones or α‐hydroxy‐allenes from aldehydes. The mechanisms involved were also investigated.
Fe-Catalyzed tandem cyclization for the synthesis of 3-nitrofurans from homopropargylic alcohols and Al(NO<sub>3</sub>)<sub>3</sub>·9H<sub>2</sub>O
作者:Ting Wang、Yong Jiang、Yanyan Wang、Rulong Yan
DOI:10.1039/c8ob01184b
日期:——
Al(NO3)3·9H2O as a nitro source for the synthesis of 3-nitrofurans from homopropargylic alcohols through Fe-catalyzed tandem cyclization is described. In this transformation, the substituted nitrofurans are obtained through nitration and cyclization. The substrate homopropargylic alcohols with different groups participate smoothly in this process and the desired substituted nitrofurans were obtained