A one-step conversion of esters to secondary alcohols with LiBH4-RMgX

Comins, Daniel L.; Herrick, James J.

doi:10.1016/s0040-4039(01)80147-7

Cited by 32 publications

(7 citation statements)

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“…As outlined above, vinyl Grignard reagents normally give this transformation only as a side reaction. 41 A vinylcopper compound is the reagent of choice if selective 1,4-addition is the goal. 42 Thus, we investigated the cleavage of a bornane sultam auxiliary using a vinylcopper compound (obtained by transmetallation of vinylmagnesium chloride with copper iodide) for one example.…”

Section: Investigations Directed Towards the Selective Formation Of B...mentioning

confidence: 99%

Synthesis of enantiomerically pure divinyl- and diallylcarbinols

Schmidt

Wildemann

2002

J. Chem. Soc., Perkin Trans. 1

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reactions of organo-metal compounds reactions of organo-metal compounds O 0350 -065Synthesis of Enantiomerically Pure Divinyl-and Diallylcarbinols.-The novel synthesis of enantiomerically pure α-chiral divinyl-and diallylcarbinols involves the treatment of acylated bornane sultams and oxazolidinones with excess of vinyl-or allylmetal compounds. For the preparation of divinylcarbinols, acylated bornane sultams are the starting materials of choice, whereas diallylcarbinols can be prepared from both types of acyl derivatives. The chemoselective formation of derivative (XII) is in particular remarkable since the ester group is not attacked by application of stoichiometric amounts of vinyl metal compound (II). Two examples for the application of the obtained carbinols in metathesis reactions are given, as well as reaction conditions which lead to selective formation of chiral butenones such as (X).

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Section: Investigations Directed Towards the Selective Formation Of B...mentioning

confidence: 99%

Synthesis of enantiomerically pure divinyl- and diallylcarbinols

Schmidt

Wildemann

2002

J. Chem. Soc., Perkin Trans. 1

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“…After complete conversion, addition of a Grignard reagent at –78 °C gave the secondary alcohol in high yield and with a high level of diastereoselectivity, explained on the basis of a chelation‐controlled model. The preparation of 35 as a single diastereoisomer from ester 34 , as depicted in Scheme , illustrates the efficiency of this approach,52 which nicely complements the related sequence described by the Commins group that allows one to access the other diastereoisomer 53…”

Section: Reactivity Towards Nucleophilesmentioning

confidence: 64%

Aluminum Acetals in Organic Synthesis

et al. 2013

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Aluminum acetals are easily obtained from esters and lactones by reduction with aluminum hydrides. These thermally unstable tetrahedral intermediates have found applications in organic synthesis, with various methodologies taking advantage both of the stabilities of these aluminum species at low temperatures and of their tendencies to undergo rearrangement into the corresponding aldehydes. Efficient one‐pot transformations can be achieved from aluminum acetals under ionic and radical conditions. A comprehensive overview of the reactivity of these species, including the most recent advances in this field, is presented in this microreview.

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“…As previously discussed by Comins and Herrick, the use of a borohydride/Grignard as a hybrid alkylating/reducing mixture could be of interest for a one pot synthesis of secondary alcohols. We hypothesized that BuMgBH 4 would be able to accomplish this without the need for a multicomponent reaction mixture. , To illustrate tandem reactivity toward organic substrates we probed the reaction of BuMgBH 4 with a series of Weinreb amides.…”

Section: Resultsmentioning

confidence: 94%

“…The tandem reactivity (i.e., multiple reactions in one step) and utility of a simple borohydride/Grignard mixture was demonstrated by Comins et al, who reacted standard RMgX reagents in various ratios with LiBH 4 . The reaction of these reagents with an ester substrate provided secondary alcohols as the major product instead of the tertiary alcohols observed using solely the Grignard reagent . Secondary alcohols are desirable both as an intermediate synthon, as well as a chiral precursor for pharmaceuticals and asymmetric catalysis .…”

Section: Introductionmentioning

confidence: 99%

“…The reaction of these reagents with an ester substrate provided secondary alcohols as the major product instead of the tertiary alcohols observed using solely the Grignard reagent. 27 Secondary alcohols are desirable both as an intermediate synthon, as well as a chiral precursor for pharmaceuticals and asymmetric catalysis. 28 The advantage of an alkyl magnesium borohydride would be a single reagent that can be used in Grignard reactions while also providing a reducing hydride source.…”

Section: ■ Introductionmentioning

confidence: 99%

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Teaching an Old Reagent New Tricks: Synthesis, Unusual Reactivity, and Solution Dynamics of Borohydride Grignard Compounds

et al. 2022

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Grignard reagents of the general formula RMgX (X = Cl − , Br − , I − ) have been utilized in various chemistries for over 100 years. We report that replacing the halide in a Grignard reagent with a reactive borohydride anion adds a new synthetic dimension for these influential compounds. We synthesized the series RMgBH 4 (R = Et, n-Bu, Ph, Bn) and characterized the reactivity toward both organic and inorganic molecules. Using butylmagnesium borohydride (BuMgBH 4 ) as an exemplar, we demonstrate that these compounds possess unique reactivity due to the presence of reducing borohydride groups, resulting in tandem reactivity with organic amides/esters to generate secondary and primary alcohols. Molecular dynamics simulations indicate the stability of BuMgBH 4 is comparable to that of Mg(BH 4 ) 2 + MgBu 2 , validating the Schlenk equilibrium in borohydride Grignard compounds. Metadynamics simulations confirm that the equilibrium is kinetically accessible through solvent-mediated processes. BuMgBH 4 also reacts with CO 2 and NH 3 , revealing potential uses for CO 2 utilization and as a mixed-anion metal borohydride/amide precursor.

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A one-step conversion of esters to secondary alcohols with LiBH4-RMgX

Cited by 32 publications

References 1 publication

Synthesis of enantiomerically pure divinyl- and diallylcarbinols

Synthesis of enantiomerically pure divinyl- and diallylcarbinols

Aluminum Acetals in Organic Synthesis

Teaching an Old Reagent New Tricks: Synthesis, Unusual Reactivity, and Solution Dynamics of Borohydride Grignard Compounds

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