Mixed AggregAte (MAA): A Single Concept for All Dipolar Organometallic Aggregates. 2. Syntheses and Reactivities of Homo/HeteroMAAs

Abstract

6. Conclusion 7706 Author Information 7706 Biographies 7707 Acknowledgment 7707 Abbreviations Used 7707 References 7708the corresponding allyl-and propargylchromium reagents that further react with a variety of electrophiles to afford the corresponding adducts in high yields. 102 Bu 6 CrLi 3 similarly behaves as a formal two-electron reductant with ketones and esters bearing a leaving group at the α-position to produce enolates that are intercepted with a variety of electrophiles with high selectivities (Table 8). 103 Such enolates are also capable of reacting with oxiranes to afford γand β-hydroxy esters, depending on the Lewis acid used as promoter. 2143.2.2. Two-Electron Transfers from M,Mn-HeteroMAAs (M = Li, MgX). In 1976, Cahiez et al. disclosed the possible reduction in THF of alkenyl bromides or iodides, as well as aryl chlorides or bromides, using i-PrMgCl in the presence of a catalytic amount of MnCl 2 . 215 The authors proposed the in situ formation of unstable i-Pr 3 MnMgCl and its decomposition by β-elimination to H 3 MnMgCl; reaction of the latter with the halide would then afford an unstable Mn(IV) intermediate, able Scheme 23 Scheme 24 Scheme 21 Scheme 22

Trans-Metal-Trapping Meets Frustrated-Lewis-Pair Chemistry: Ga(CH2SiMe3)3-Induced C–H Functionalizations

“…Recent examples include regioselective dimagnesiation of N , N -dimethylaniline 11 and the N-heterocyclic carbene (NHC) 1,3-bis(2,6-diisopropylphenyl)imidazol-2-ylidene (IPr), 12 where the supramolecular structure of the mixed sodium/magnesium base templates the regioselectivity of the deprotonation reaction. 13 …”

Chiral Lithium Amido Zincates for Enantioselective 1,2‐Additions: Auto‐assembling Reagents Involving a Fully Recyclable Ligand

“…At the turn of this century, a sustained attention has been devoted to the use, in organic synthesis, of organo(bi)metallic “ate‐complex” species, which combine, in a synergic operation, specific properties of two organometallic compounds. Long standing problems related to the chemo‐, regio‐, and stereoselectivities of general reactions, such as the deprotonation or the creation of C−C bonds, have been elegantly solved thanks to these tools . Several combinations such as those associating two of the Li, Mg, Al, and Zn derivatives have thus emerged, having shown a strong capacity to both effectively allow dehalogenative metalations or react as bases for aromatic deprotonation reactions .…”

“…Long standing problems related to the chemo‐, regio‐, and stereoselectivities of general reactions, such as the deprotonation or the creation of C−C bonds, have been elegantly solved thanks to these tools . Several combinations such as those associating two of the Li, Mg, Al, and Zn derivatives have thus emerged, having shown a strong capacity to both effectively allow dehalogenative metalations or react as bases for aromatic deprotonation reactions . But less is known about the nucleophilic properties of these multicomponent reactants, and very few studies involving chiral lithium magnesates, zincates, and aluminates, to run enantioselective nucleophilic additions are mentioned in the literature.…”

Atom Efficient Magnesiation of N‐Substituted Alkyl Indoles with a Mixed Sodium‐Magnesium Base

“…In the last fifteen years, numerous research groups have developed mixed metal reagents as new tools to deprotometallate sensitive aromatic compounds . In the context of indoles, Uchiyama et al have studied both the direct ortho ‐cupration and ‐alumination of N ‐boc‐indoles using the lithium cuprate [MeCu(TMP)(CN)Li 2 ] and lithium aluminate [ i Bu 3 Al(TMP)Li] reagents achieving C2‐selective outcomes .…”