Smooth and quantitative deprotection of a wide range of acetals and ketals [Eq. (a); R, R(1)=alkyl, aryl, H] under neutral to mildly basic conditions was achieved with catalytic quantities of cerium ammonium nitrate (CAN). The reaction conditions are compatible with a variety of sensitive functional groups, and aldehydes can be liberated from acetals without being oxidized to the corresponding carboxylic
Evidence for oxacarbenium ion intermediates in the Lewis acid promoted cleavage of spirocyclic dioxanes
作者:Lee A. Newitt、Patrick G. Steel
DOI:10.1039/a701764b
日期:——
Studies on the Lewis acid mediated cleavage of spiro-1,3-dioxanes
indicate that this process proceeds via an oxacarbenium ion
intermediate. With the correct choice of nucleophile and Lewis acid,
high selectivities can be obtained.
Observations on the generation of organozinc carbenoids from acetals and ketals
作者:William B. Motherwell、Donogh J.R. O'Mahony、Matthew E. Popkin
DOI:10.1016/s0040-4039(98)01001-6
日期:1998.7
The use of acetals and ketals as direct precursors for organozinc carbenoid chemistry is illustrated by their direct conversion to alkenes in a one pot operation. Aryl acetals can also be used as precursors for the cyclopropanation of cyclohexene.
Grosu, Ion; Camacho, Del Carmen Brigida; Toscano, Alfredo, Journal of the Chemical Society. Perkin transactions I, 1997, # 5, p. 775 - 781
作者:Grosu, Ion、Camacho, Del Carmen Brigida、Toscano, Alfredo、Ple, Gerard、Mager, Sorin、Martinez, Roberto、Gavino, Ruben Ramirez
DOI:——
日期:——
Mild and chemoselective catalytic deprotection of ketals and acetals using cerium(IV) ammonium nitrate
作者:Ali Ates、Arnaud Gautier、Bernard Leroy、Jean-Marc Plancher、Yannick Quesnel、Jean-Christophe Vanherck、István E Markó
DOI:10.1016/j.tet.2003.03.002
日期:2003.11
Cerium(IV) ammonium nitrate (CAN) is a powerful, though mild, reagent for the efficient and selective removal of a range of ketals and acetals. This novel deprotection method requires only catalytic amounts of CAN and tolerates a variety of functional and protecting groups. Mechanistic insights suggest that the Ce(IV) salts act as unique Lewis acids and not as redox active species.