Synthesis of α-hydroxy ketones by copper（Ⅰ）-catalyzed hydration of propargylic alcohols: CO2 as a cocatalyst under atmospheric pressure

Inexpensive and efficient Cu(Ⅰ) catalysis is reported for the synthesis of α-hydroxy ketones from propargylic alcohols, CO2, and water via tandem carboxylative cyclization and nucleophilic addition reaction. Notably, hydration of propargylic alcohols can be carried out smoothly under atmospheric CO2 pressure, generating a series of α-hydroxy ketones efficiently and selectively. This strategy shows great potential for the preparation of valuable α-hydroxy ketones by using CO2 as a crucial cocatalyst under mild conditions.

Condensation reaction of β-triphenylgermanyl propionic acid with α-hydroxy phosphonic ester and the structure of the products

<正> The sterically hindered condensation of β-triphenylgermanyl propionic acid withα-hydroxy phosphonic ester has been studied.The failure of conventional ways of the condensation is probablydue to the bulky groups Ph3Ge-and-P（O）（OR）2.However,several novel O,O-dialkyl-α-（β-triphenylgermanyl）propionoxy phosphonic esters have been synthesized successfully in good yields by using DCC catalyzed bypyridine or HOBt.The reactivity has much to do with the steric hindrance of the groups R.Thelarger the OR,the slower the reaction rate is.All the new products were characterized by1H NMR,IRspectra,MS and elemental analyses.A single crystal A1was obtained and the structure was determined byX-ray diffraction.Preliminary bioassays showed that the new products exhibit antitumor activity.

Diverse synthesis of the C ring fragment of bryostatins via Zn/Cu-promoted conjugate addition of α-hydroxy iodide with enone

A convergent approach to 1,5-hydroxy ketones,the general precursors for constructing the C ring of bryostatins,has been developed via a Zn/Cu-promoted conjugate addition of a-hydroxy iodides with enones.The reaction leads to direct formation of the C21-C22 bond and tolerates diverse functionalities at the C17-,C18-and C24-positions.The approach also enables a more concise synthesis of the known C ring intermediate(10 longest linear steps and 14 total steps),in contrast to its previous synthesis(17 longest linear steps and 22 total steps) in our total synthesis of bryostatin 8.

2-Hydroxymalonitrile——A Useful Reagent for One-step Synthesis of α-Hydroxy Esters

α-Hydroxy carboxylic esters and their derivatives are key substructures in a variety of biologically active natural products and numerous pharmaceuticals[1-3].A variety of methods for the synthesis of α-hydroxyesters via homologation of aldehydes or ketones have been developed and frequently used in organic synthesis[4-14].These approaches are generally based on the following routes（Scheme 1）.

Synthesis of Quaternary α-Hydroxy Phosphonates via Direct Hydroxylation of Phosphonate Compounds

It was found for the first time that Cs_(2)CO_(3) serves as highly efficient catalyst for the direct hydroxylation reactions of phosphonates under mild conditions.This reaction provides an efficient approach to quaternaryα-hydroxy phosphonates,which possess intriguing biological activities and are widely used in many areas.

Microwave-assisted synthesis of α-hydroxy aromatic ketones from α-bromo aromatic ketones in water

A reaction of α-bromo aromatic ketones in water with microwave irradiation gave the corresponding α-hydroxy aromatic ketones in good yields. The use of microwaves was found to significantly improve yields and shorten the reaction time. This reaction afforded a very clean, convenient method for the synthesis of α-hydroxy aromatic ketones.

Crystal Structure of O，O－Diethyl－α－（β－triphenylgermanyl）－propionoyloxy Methylphosphonate

C26H31GeO5P is monoclinic,space group P21/c,a=14.287（4）,b=8.045（2）,c=23.381（6）,β=103.79（2）°,V=2622.7,Mr=527.10,Z=4,Dx=1.34g/cm3,μ=12.4cm.F（000）=1096.The final R=0.051 and Rw=0.057 for 2446 observed unique reflections[I≥3σ（I）.The results indicated that all non-hydrogen atoms between phosphorus and germanium in the title compound were located almost in coplane with farthest deviation of atom Ge defined by 0. 3657.The values of Ge-C（phenyl） and Ge-C（alkyl） bond distance are 1.938（5）,1.945（5） and 1.976（5）,respectively.

A.Flavus Mediated Biotransformations for the Syntheses of Active A-oxyfunctionalized Compounds

1 Results Biotransformations are enzyme- and whole cell-catalysed conversions of non-natural substrates to products.They are important tools in organic synthesis,especially for the syntheses of chiral molecules,where the reactions catalysed may be asymmetric syntheses or the resolution of racemates.The main advantages associated with the use of single enantiomer compounds are increased specificity and the avoidance of adverse side effects[1].Whole cell reactions are advantegous over enzyme-catalyzed rea...