- Microwave-assisted green synthesis of 1,1-diacetates (acylals) using selectfluor as an environmental-friendly catalyst under solvent-free conditions
-
An efficient and simple procedure has been developed for the acetylation of aldehyde by selectfluor [1-(chloromethyl)-4-fluoro-1,4-diazoniabicyclo[2,2,2]octane bis(tetrafluoroborate)] as a chemoselective and environmentally friendly catalyst under solvent-free conditions or microwave irradiation. The application of microwave irradiation improved the yields and reduced the reaction times. In this study, selective conversion of aldehydes was observed in the presence of ketones, and the deprotection of 1,1-diacetates has also been achieved using selectfluor in water as green solvent in reflux conditions. The methodology provides synergy of microwave irradiation which offers several advantages such the simple work-up procedure, short reaction time, excellent yields and environmentally benign procedure.
- Rezayati, Sobhan,Hajinasiri, Rahimeh,Erfani, Zahra
-
p. 2567 - 2576
(2016/03/16)
-
- Zinc zirconium phosphate as an efficient catalyst for chemoselective synthesis of 1,1-diacetates under solvent-free conditions
-
In the present study, a mild, rapid, and efficient method for the protection of aldehydes with acetic anhydride (AA) in the presence of zinc zirconium phosphate (ZPZn) as a nano catalyst, at room temperature is reported. Selective conversion of aldehydes was observed in the presence of ketones. Under these conditions, different aldehydes bearing electron-withdrawing and electron-donating substituents were reacted with AA and the corresponding 1,1-diacetates (acylals) were obtained in high to excellent yields. The steric and electronic properties of the different substrates had a significant influence on the reaction conditions. Also, the deprotection of 1,1-diacetates has been achieved using this catalyst in water. This nanocatalyst was characterized by several physico-chemical techniques. It was recovered easily from the reaction mixture, regenerated and reused at least 7 times without significant loss in catalytic activity. This protocol has the advantages of easy availability, stability, reusability of the eco-friendliness, chemoselectivity, simple experimental and work-up procedure, solvent-free conditions and usage of only a stoichiometric amount of AA.
- Hajipour, Abdol R,Karimi, Hirbod
-
p. 1945 - 1955
(2015/12/30)
-
- Cobalt-catalyzed addition of azoles to alkynes
-
A ternary catalytic system consisting of a cobalt salt, a diphosphine ligand, and a Grignard reagent promotes syn-addition of an azole C(2)-H bond across an unactivated internal alkyne with high chemo-, regio-, and stereoselectivities under mild conditions. Mechanistic experiments suggest that the reaction involves oxidative addition of the oxazolyl C-H bond to the cobalt center, alkyne insertion into the Co-H bond, and reductive elimination of the resulting diorganocobalt species.
- Ding, Zhenhua,Yoshikai, Naohiko
-
supporting information; experimental part
p. 4180 - 4183
(2010/11/19)
-
- Chemoselective synthesis of 1,1-diacetates from aldehydes in the presence of Al(HSO4)3 under mild solvent-free conditions
-
A novel efficient procedure has been developed for the preparation of acylals in high yields by reaction of the corresponding aldehydes with acetic anhydride in the presence of Al(HSO4)3 as catalyst under mild (room temperature) solvent-free conditions.
- Mirjalili,Zolfigol,Bamoniri,Amrollahi,Sheikhan
-
p. 852 - 854
(2008/03/11)
-