59163-81-4Relevant articles and documents
Exploring Site Selectivity of Iridium Hydride Insertion into Allylic Alcohols: Serendipitous Discovery and Comparative Study of Organic and Organometallic Catalysts for the Vinylogous Peterson Elimination
Li, Houhua,Fiorito, Daniele,Mazet, Clément
, p. 1554 - 1562 (2017/08/15)
The vinylogous Peterson elimination of a broad range of primary, secondary, and tertiary silylated allylic alcohols by two distinct and complementary catalytic systems - a cationic iridium complex and a Br?nsted acid - is reported. These results are unexpected. Nonsilylated substrates are typically isomerized into aldehydes and silylated allylic alcohols into homoallylic alcohols with structurally related iridium complexes. Although several organic acids and bases are known to promote the vinylogous Peterson elimination, the practicality, mildness, functional group tolerance, and generality of both catalysts are simply unprecedented. Highly substituted C=C bonds, stereochemically complex scaffolds, and vicinal tertiary and quaternary (stereo)centers are also compatible with the two methods. Both systems are stereospecific and enantiospecific. After optimization, a vast number of dienes with substitution patterns that would be difficult to generate by established strategies are readily accessible. Importantly, control experiments secured that traces of acid that may be generated upon decomposition of the in situ generated iridium hydride are not responsible for the activity observed with the organometallic species. Upon inspection of the reaction scope and on the basis of preliminary investigations, a mechanism involving iridium-hydride and iridium-allyl intermediates is proposed to account for the elimination reaction. Overall, this study confirms that site selectivity for [Ir-H] insertion across the C=C bond of allylic alcohols is a key parameter for the reaction outcome.
Conjugated diene-assisted allylic C-H bond activation: Cationic Rh(I)-catalyzed syntheses of polysubstituted tetrahydropyrroles, tetrahydrofurans, and cyclopentanes from Ene-2-dienes
Li, Qian,Yu, Zhi-Xiang
supporting information; experimental part, p. 4542 - 4543 (2010/06/13)
C-H activation followed by addition to alkenes is challenging in the current C-H activation/functionalization field. We report herein an unprecedented diene-assisted transition-metal-catalyzed activation of allylic C-H bonds and their subsequent insertion
First regio- and enantioselective chromium-catalyzed homoallenylation of aldehydes
Coeffard, Vincent,Aylward, Miriam,Guiry, Patrick J.
supporting information; experimental part, p. 9152 - 9155 (2010/03/03)
Game, set, and match: The first regio- and enantioselective version of the title reaction is described. The chiral catalyst prepared in situ from CrCl 3 and a non-C2-symmetric bis(oxazoline) ligand 1 affords the valuable chiral ss-al
