a-Acetoxy esters or amides were synthesized directly and in one portion from aldehydes and alcohols or amines by onecarbon homologation using a masked acyl cyanide reagent bearing an acetyl group.The development of an acyl carbanion 1 is of scientific significance because of the challenges associated with the nature of carbonyl functionality, and is of practical significance from the point of view of flexibility in synthesis routes and methods. With a focus on the latter aspect, a number of chemists have developed elaborate chemical species that are synthetic equivalents of acyl anions. 2

Synthesis of a-siloxy esters via a one-pot reaction from various aldehydes and alcohols using a masked acyl cyanide (MAC) reagent bearing tert-butyldimethylsilyl group is described.

Here, we developed two pairs of high-contrast chemical probes and their RNA aptamers with distinct readout channels that permitted simultaneous live-cell imaging of endogenous β-actin and cortactin mRNAs. Application of this technology allowed the direct observation of the formation process of stress granules, protein-RNA assemblies essential for cellular response to the environment.

A highly selective mono-C-allylation of pentaethyl diethylenetriaminepentaacetate was achieved with allyl bromide and potassium carbonate via a newly developed elaborate procedure based on Stevens rearrangement. It is contrastive that the conservative one-pot procedure gave a complicated mixture.Diethylenetriaminepentaacetic acid (DTPA, 1) is a wellknown chelating agent of heavy-metal cations (Scheme 1). 1 To design the hybrid molecules possessing both a peculiarity of the metal cations and an orthogonal property such as a specific affinity for particular organs or cells, a number of DTPA derivatives have been synthesized. [2][3][4][5]7,8 A major molecular design is shown as 2, which can be synthesized from commercially available DTPA dianhydride and an amine (H 2 NR 1 ). Despite the simplicity of this synthetic strategy, it should be reconsidered; the loss of one of the five carboxylates decreases the binding ability. 3,9 Recently, syntheses of DTPA derivatives with five free carboxylates that contain a linker-and-functionality group at a carbon of the framework, such as in 3 and 4, have been reported via a number of C-N bond-formation reactions. 4The loss of large amounts of halogen salts, however, makes these processes unsustainable.In contrast, fundamental molecule 1 has been prepared in a highly sustainable industrial-scale process via additiondehydration reactions followed by hydrolysis of pentanitrile 5. 6 We recently developed a carbon-carbon bondforming reaction that enables addition of a side chain directly onto the DTPA framework to afford 6. 5 However, poor reproducibility on a large scale has remained problematic. In this process, highly moisture-or air-sensitive carbanion species must be generated with strict stoichiometric control because of the five reacting groups in the DTPA framework. Similar procedures were reported by Keana et al. 7 and Muller et al. 8 to afford 7 in only 32-36% yield. Accordingly, the efficient methods for the synthesis of DTPA-hybrid molecules have not yet been developed.In this paper, we report a highly practical and reproducible mono-C-allylation reaction of 8 5 using allyl bromide (9) in DMF in the presence of potassium carbonate (K 2 CO 3 ) as an essential base (Scheme 2). Importantly, excessively strict control of the quantity of each reagent is not required. It is believed that this key reaction proceeds via the Stevens rearrangement, 10 N-allylation followed by Cmigration. 11 However, results of our preliminary attempts, conservative procedures of Stevens rearrangement reported in a number of previous papers, 10 were described at Scheme 1 Previous synthetic routes of DTPA derivatives for candidates of MRI agents X A