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Exploiting Synergistic Effects in Organozinc Chemistry for Direct Stereoselective C‐Glycosylation Reactions at Room Temperature
Author(s) -
HernánGómez Alberto,
Orr Samantha A.,
Uzelac Marina,
Kennedy Alan R.,
Barroso Santiago,
Jusseau Xavier,
Lemaire Sébastien,
Farina Vittorio,
Hevia Eva
Publication year - 2018
Publication title -
angewandte chemie
Language(s) - English
Resource type - Journals
eISSN - 1521-3757
pISSN - 0044-8249
DOI - 10.1002/ange.201805758
Subject(s) - chemistry , stereoselectivity , reagent , catalysis , lewis acids and bases , aryl , glycosylation , glycosyl , zinc , coupling reaction , transition metal , combinatorial chemistry , medicinal chemistry , stereochemistry , organic chemistry , alkyl , biochemistry
Pairing a range of bis(aryl) zinc reagents ZnAr 2 with the stronger Lewis acidic [(ZnAr F 2 )] (Ar F =C 6 F 5 ), enables highly stereoselective cross‐coupling between glycosyl bromides and ZnAr 2 without the use of a transition metal. Reactions occur at room temperature with excellent levels of stereoselectivity, where ZnAr F 2 acts as a non‐coupling partner although its presence is crucial for the execution of the C(sp 2 )–C(sp 3 ) bond formation process. Mechanistic studies have uncovered a unique synergistic partnership between the two zinc reagents, which circumvents the need for transition‐metal catalysis or forcing reaction conditions. Key to the success of the coupling is the avoidance of solvents that act as Lewis bases versus diarylzinc compounds (e.g. THF).