26717-67-9Relevant articles and documents
Preparation of mono-substituted malonic acid half oxyesters (SMAHOs)
Condon, Sylvie,Le Gall, Erwan,Pichon, Christophe,Presset, Marc,Xavier, Tania
supporting information, p. 2085 - 2094 (2021/09/02)
The use of mono-substituted malonic acid half oxyesters (SMAHOs) has been hampered by the sporadic references describing their preparation. An evaluation of different approaches has been achieved, allowing to define the best strategies to introduce diversity on both the malonic position and the ester function. A classical alkylation step of a malonate by an alkyl halide followed by a monosaponification gave access to reagents bearing different substituents at the malonic position, including functionalized derivatives. On the other hand, the development of a monoesterification step of a substituted malonic acid derivative proved to be the best entry for diversity at the ester function, rather than the use of an intermediate Meldrum acid. Both these transformations are characterized by their simplicity and efficiency, allowing a straightforward access to SMAHOs from cheap starting materials.
Enantioselective α-Amination of Acyclic 1,3-Dicarbonyls Catalyzed by N-Heterocyclic Carbene
Santra, Surojit,Maji, Ujjwal,Guin, Joyram
supporting information, p. 468 - 473 (2020/02/04)
Herein, we describe a method for the catalytic enantioselective α-amination of α-substituted acyclic 1,3-ketoamides and 1,3-amidoesters that affords the products possessing N-substituted quaternary stereocenters with a chiral N-heterocyclic carbene (NHC). The reaction is based on the utilization of an intrinsic Br?nsted base characteristic of NHC that enables the catalytic formation of a chiral ion pair comprising the enolate and the azolium ion. A series of challenging open-chain α-substituted 1,3-dicarbonyls are aminated via this method with ee's of ≤99%.
Substrate-directable electron transfer reactions. Dramatic rate enhancement in the chemoselective reduction of cyclic esters using SmI2-H 2O: Mechanism, scope, and synthetic utility
Szostak, Michal,Spain, Malcolm,Choquette, Kimberly A.,Flowers, Robert A.,Procter, David J.
supporting information, p. 15702 - 15705 (2013/11/06)
Substrate-directable reactions play a pivotal role in organic synthesis, but are uncommon in reactions proceeding via radical mechanisms. Herein, we provide experimental evidence showing dramatic rate acceleration in the Sm(II)-mediated reduction of cyclic esters that is enabled by transient chelation between a directing group and the lanthanide center. This process allows unprecedented chemoselectivity in the reduction of cyclic esters using SmI2-H2O and for the first time proceeds with a broad substrate scope. Initial studies on the origin of selectivity and synthetic application to form carbon-carbon bonds are also disclosed.
