The reactions of styrene and trans-β-methylstyrene with lead tetraacetate in acetic acid are greatly influenced by ultrasonic irradiation to give products resulting mostly from radical chain pathways, whereas mechanical agitation gives products only from ionic processes.
of a method which is used for the functional group transformations depends on its simplicity, high yields of the desired products, short reaction times, low cost of the process and ease of the work-up procedure.Between the several methods available for the protection of aldehydes, acylal formation is often preferred due to the ease of preparation and the stability of the produced 1,1-diacetate towards
Mild and Chemoselective Synthesis and Deprotection of Geminal Diacetates Catalyzed by Titanium(IV) Halides
作者:Jae-Sang Ryu、Misuk Jung、Jieun Yoon、Hak Kim
DOI:10.1055/s-0029-1218849
日期:2010.8
A novel, mild, and chemoselective method was developed for the preparation of gem-diacetates from aldehydes and acetic anhydride in the presence of titanium(IV) fluoride (1-5 mol%) under solvent-free conditions at room temperature. The reaction showed a high chemoselectivity toward aldehydes in the presence of ketones. Moreover, titanium(IV) fluoride also catalyzed the deprotection of gem-diacetates
Chemoselective synthesis and deprotection of 1,1-diacetates have been performed in good yields and in the absence of any solvent by zeolite HSZ-360 as a new reusable catalyst.