The bioinspired design of a reagent allows the functionalization of C<sub>α</sub>–H of α,β-unsaturated carbonyl compounds via the Baylis–Hillman chemistry under ambient conditions
A rationally designed reagent capable to affect alkylation at C[small alpha] of [small alpha], [small beta]-unsaturated carbonylcompounds is reported. The reaction proceeded at room temperature without any additives. The pH and H-Bond...
Process for preparing 2-chloro-6-Halogeno-3-alkyl-4H-chrom en-4-one or 2-chloro-3-alkyl-4H-chromen-4-one derivatives
申请人:Bayer CropScience AG
公开号:EP1614685A1
公开(公告)日:2006-01-11
The present invention relates to a process for preparing 2-chloro-6-halogeno-3-alkyl-4H-chromen-4-one or 2-chloro-3-alkyl-4H-chromen-4-one derivatives and to compounds that can be prepared with this process and to compounds useful for this process.
Allyl esters of 3-carboxylcoumarins undergo facile decarboxylative coupling at just 25−50 °C. This represents the first extension of decarboxylative C−C bond-forming reactions to the coupling of aromatics with sp3-hybridized electrophiles. Finally, the same concept can be applied to the sp2−sp3 couplings of pyrones and flavones. Thus, a variety of biologically important heteroaromatics can be readily
3-羧基香豆素的烯丙酯在 25−50 °C 下即可轻松脱羧偶联。这代表了脱羧CC键形成反应首次扩展到芳香族化合物与sp 3杂化亲电子试剂的偶联。最后,相同的概念可以应用于吡喃酮和黄酮的 sp 2 -sp 3偶联。因此,多种生物学上重要的杂芳族化合物可以很容易地官能化,而不需要更标准的交叉偶联反应通常需要的强碱或化学计量的有机金属化合物。
Practical Large-Scale Regioselective Zincation of Chromone Using TMPZnCl·LiCl Triggered by the Presence or Absence of MgCl<sub>2</sub>
作者:Lydia Klier、Dorothée S. Ziegler、René Rahimoff、Marc Mosrin、Paul Knochel
DOI:10.1021/acs.oprd.7b00032
日期:2017.4.21
commercially available amide base TMPZnCl·LiCl (TMP = 2,2,6,6-tetramethylpiperidyl). Additionally, in the presence of a Lewis acid such as MgCl2, zincation using TMPZnCl·LiCl occurs at C(2). These metalation reactions are carried out on a 50 mmol scale, and the metalation selectivities have been compared with the corresponding small-scale reactions (2 mmol). The resulting zinc organometallics undergo smooth