Lithium- α-lithioacetate and β-lithiopropionate: useful intermediates in organic synthesis
作者:Isidro M Pastor、Miguel Yus
DOI:10.1016/s0040-4039(00)00794-2
日期:2000.7
The reaction of chloroacetic acid and 3-chloropropionic acid with a base (LDA or BunLi, respectively) and then with an excess of lithium and a catalytic amount of 4,4′-di-tert-butylbiphenyl (DTBB, 5%) in the presence of different electrophiles [ButCHO, PhCHO, Et2CO, (CH2)5CO, PhCOMe] in THF at −78°C leads, after hydrolysis with water, to the expected hydroxy acids, which in the second case are directly
氯乙酸和3-氯丙酸与碱(分别为LDA或Bu n Li)的反应,然后与过量的锂和催化量的4,4'-二叔丁基联苯(DTBB,5%)反应在不同的亲电子试剂的存在下[卜吨CHO,苯甲醛,等2 CO,(CH 2)5 CO,PhCOMe]在THF中在-78℃下引线,与水水解后,与预期的羟基酸,其中在所述第二在酸性条件下,直接将其环化,得到预期的γ-内酯。
Synthesis of Perhydrooxazinones from 2-Aza-3-Trimethylsilyloxy-1,3-Butadiene. A General Route to 3,3-Disubstituted-β-Hydroxy Acids
1-Phenyl-2-aza-3-trimethylsilyloxy-1,3-butadiene reacts with aliphatic, aromatic and cyclic ketones to give in good to excellent yields 6,6-disubstituted-1,3-perhydro-oxazin-4-ones which, in turn, have been readily converted into β-hydroxy carboxylic acids.
Disclosed herein are KCNQ potassium channels modulators of formula (I)
wherein ring G
1
, R
1
, and R
2
are as defined in the specification. Compositions comprising such compounds; and methods for treating conditions and disorders using such compounds and compositions are also described.
Aldol-type Reactions of Unmasked Iodoacetic Acid with Carbonyl Compounds Promoted by Samarium Diiodide: Efficient Synthesis of Carboxylic 3-Hydroxyacids and Their Derivatives
作者:José M. Concellón、Carmen Concellón
DOI:10.1021/jo060118j
日期:2006.6.1
An easy, direct, general, and efficient samarium diiodide-mediated preparation of 3-hydroxyacids 1 in high yield by reaction of different aldehydes or ketones with commercially available iodoacetic acid is described. The application of different esterification procedures to the crude 3-hydroxyacids so obtained afforded the corresponding 3-hydroxyesters. Also, the cyclization of crude 3-hydroxycarboxylic
Intramolecular Insertions into Unactivated C(sp<sup>3</sup>)–H Bonds by Oxidatively Generated β-Diketone-α-Gold Carbenes: Synthesis of Cyclopentanones
作者:Youliang Wang、Zhitong Zheng、Liming Zhang
DOI:10.1021/jacs.5b02280
日期:2015.4.29
Generation of reactive α-oxogold carbene intermediates via gold-catalyzed oxidation of alkynes has become an increasing versatile strategy of replacing hazardous diazo carbonyl compounds with benign and readily available alkynes in the development of efficient synthetic methods. However, one of the hallmarks of metal carbene/carbenoid chemistry, i.e., insertion into an unactivated C(sp(3))-H bond