1357255-96-9Relevant academic research and scientific papers
Methodology for in situ protection of aldehydes and ketones using trimethylsilyl trifluoromethanesulfonate and phosphines: Selective alkylation and reduction of ketones, esters, amides, and nitriles
Yahata, Kenzo,Minami, Masaki,Yoshikawa, Yuki,Watanabe, Kei,Fujioka, Hiromichi
, p. 1298 - 1307 (2014/01/06)
A methodology for selective transformations of ketones, esters, Weinreb amides, and nitriles in the presence of aldehydes has been developed. The use of a combination of PPh3-trimethylsilyl trifluoromethanesulfonate (TMSOTf) promotes selective transformation of aldehydes to their corresponding, temporarily protected, O,P-acetal type phosphonium salts. Because, hydrolytic work-up following ensuing reactions of other carbonyl moieties in the substrates liberates the aldehyde moiety, a sequence involving aldehyde protection, transformation of other carbonyl groups, and deprotection can be accomplished in a one-pot manner. Furthermore, the use of PEt3 instead of PPh 3 enables ketones to be converted in situ to their corresponding O,P-ketal type phosphonium salts and, consequently, selective transformations of esters, Weinreb amides, and nitriles in the presence of ketones can be performed. This methodology is applicable to various dicarbonyl compounds, including substrates that possess heteroaromatic skeletons and hydroxyl protecting groups.
Control of transient aluminum-aminals for masking and unmasking reactive carbonyl groups
Barrios, Francis J.,Springer, Brannon C.,Colby, David A.
supporting information, p. 3082 - 3085 (2013/07/26)
A new reagent, the dimethylaluminum N,O-dimethylhydroxylamine complex, is effective at masking reactive carbonyl groups in situ from nucleophilic addition. This reagent allows chemoselective addition of reducing reagents, Grignard reagents, organolithiums, Wittig reagents, and enolates into substrates with multiple carbonyl groups. Moreover, the trapped carbonyl group, a stable aminal, can be unmasked in situ for additional synthetic manipulations.
Reversing the reactivity of carbonyl functions with phosphonium salts: Enantioselective total synthesis of (+)-centrolobine
Fujioka, Hiromichi,Yahata, Kenzo,Kubo, Ozora,Sawama, Yoshinari,Hamada, Tomohito,Maegawa, Tomohiro
supporting information; experimental part, p. 12232 - 12235 (2012/01/30)
Step saver: Carbonyl groups with lower reactivities can be transformed in the presence of more reactive ones by treatment with PPh3 (or PEt3) and TMSOTf prior to the reaction (see scheme; TMS=trimethylsilyl, Tf=trifluoromethanesulfonyl). This methodology can be applied to reduction and alkylation reactions, and enabled the short asymmetric total synthesis of (+)-centrolobine with the highest overall yield reported to date.
