Applications of cyclopropylboranes in organic synthesis. 1. A stereocontrolled route to substituted cyclopropanol derivatives

Danheiser, Rick; Savoca, A.

doi:10.1021/jo00213a048

Cited by 52 publications

(24 citation statements)

References 1 publication

(2 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Ti(O-i-Pr) 4 method, perhaps because the Ti method is heterogeneous, whereas the present method is homogeneous. Ti(O-i-Pr) 4 method, perhaps because the Ti method is heterogeneous, whereas the present method is homogeneous.…”

mentioning

confidence: 84%

“…11 [e] None of the Co and Ni catalysts, which we examined, 12 Fe(dbm) 3 and FeCl 2 (dppe) catalysts were also effective, however, the reaction was a little sluggish. 17 [d] Even MeMgBr worked as a reducing reagent in contrast to the Ti(O-i-Pr) 4 catalyzed method, wherein MeMgBr is adopted only for gem-dibromocyclopropanes. 17 [d] Even MeMgBr worked as a reducing reagent in contrast to the Ti(O-i-Pr) 4 catalyzed method, wherein MeMgBr is adopted only for gem-dibromocyclopropanes.…”

mentioning

confidence: 99%

See 1 more Smart Citation

Dimethylation and Hydrodechlorination ofgem-Dichlorocyclopropanes with Grignard Reagents Promoted by Fe(III) or Co(II) Catalyst

Nishii

Wakasugi

Tanabe

1998

Synlett

View full text Add to dashboard Cite

Reactions of gem-dichlorocyclopropanes with MeMgBr or t-BuMgCl were examined in the presence of Fe, Co, and Ni (group VIIIA, first transition series) catalysts. The Fe(dbm) 3 catalyst promoted dimethylations of gem-dichlorocyclopropanes in the presence of 4methoxytoluene or p-xylene. In contrast, CoCl 2 (dppe) conducted their hydrodechlorination.Transformations of gem-dihalocyclopropanes into functionalized cyclopropanes are useful synthetic methods, 1 due to the preparative accessibility of gem-dihalocyclopropanes. A number of reductive hydrodehalogenations were extensively studied as a basic functionalization. 2 Several efficient methods have been exploited for the double carbon-elongations mediated by the ate transient complexes of Cu, 3 B, 4 Zn, 5 and Mn. 6 Giese-type sequential stereocontrolled couplings using Bu 3 SnH were also reported. 7

show abstract

mentioning

confidence: 84%

mentioning

confidence: 99%

Dimethylation and Hydrodechlorination ofgem-Dichlorocyclopropanes with Grignard Reagents Promoted by Fe(III) or Co(II) Catalyst

Nishii

Wakasugi

Tanabe

1998

Synlett

View full text Add to dashboard Cite

show abstract

“…[14] This process has been utilized successfully in the alkylation of α-haloalkylmetals (e.g., M ϭ Mg, [15] Zn, [16] B, [17] or Cu [18] ) and allows the facile introduction of an alkyl group to the organometallic reagents. This process enables complex metallic reagents to be prepared from relatively simple and easily accessible organometallic species.…”

Section: Methodsmentioning

confidence: 99%

Transition Metal‐Catalyzed Carbon−Carbon Bond Formation with Grignard Reagents − Novel Reactions with a Classic Reagent

2004

View full text Add to dashboard Cite

Keywords: Chromium / Cobalt / Grignard reagent / Iron / Manganese Organomagnesium compounds are among the most useful organometallic reagents in organic synthesis. Besides their classical nucleophilic reactions to carbonyl compounds, Grignard reagents gain versatile reactivity when combined with various transition metal salts. In this article, we review mainly our own studies on manganese-, iron-, chromium-,

show abstract

“…13 They reported that various substituted cyclopropanols can be synthesized by the reaction of gemlithiobromocyclopropanes with alkylboranes such as trialkylboranes or catecholborane and exploiting 1,2-migration of an alkyl group or hydrogen from boron to carbon. We decided to examine this protocol using alkynylboranes as the boron component.…”

Section: Methodsmentioning

confidence: 99%

“…In the reaction of 7,7-dibromobicyclo-[4.1.0]heptane 12 (n=1), only one diastereomer was obtained, whose stereochemistry was assigned as the endo-alkynyl isomer as shown in 14a by analogy with the results of Danheiser. 13 In the case of the reaction of 8,8-dibromobicyclo[5.1.0]octane 12 (n=2), a mixture of endo and exo isomers were obtained. Furthermore, the products, in particular the exo isomers 15c (n=2, R=Ph) and 15d (n=2, R=n-Bu), were insufficiently stable to be purified and the crude products were directly silylated with TBSOTf and Et 3 N to give the separable mixture of endo isomers 16c,d and exo isomers 17c,d.…”

Section: Methodsmentioning

confidence: 99%

Cobalt Carbonyl Induced Transformations of Alkynyl- and Propadienyl-cyclopropanes

Iwasawa¹

1999

Synlett

View full text Add to dashboard Cite

A novel rearrangement of 1-(1-alkynyl)cyclopropanols to 2-cyclopenten-1-ones proceeded on complexation of their alkynyl part with Co 2 (CO) 8 . In the case of reactions of 1-alkynylcyclopropanols with an alkyl substituent on the cyclopropane ring, either 4-substituted or 5-substituted 2-cyclopenten-1-ones could be selectively obtained by appropriate choice of stereochemistry and protective group of the substrates. This rearrangement was successfully applied to the annulation of cyclopentenones onto cycloalkenes. Furthermore, the rearrangement was found to proceed catalytically on addition of triarylphosphite as a ligand. In particular, when tri(oisopropylphenyl)phosphite was used as ligand, 5-10 mol% of Co 2 (CO) 8 and 10-20 mol% of the phosphite sufficed for the efficient conversion of 1-alkynylcyclopropanols to 2-cyclopentenones. The same type of rearrangement proceeded when 1-[o-(1-alkynyl)phenyl]cyclopropanols were employed as substrate; these being converted to 2,3-dihydro-1-naphthalenone derivatives on heating their hexacarbonyldicobalt complexes in 2-propanol. Furthermore, a new type of isomerization-cyclization reaction proceeded to give 3a,4-dihydro-3H-cyclopenta[a]inden-2-one derivatives when the same reaction was carried out in the presence of DABCO. Finally a novel transformation of 1-(1,2-propadienyl)cyclopropanols into substituted 1,4-hydroquinones was developed utilizing the interaction of 1,2-propadienes and Co 2 (CO) 8 . This reaction was applied to the synthesis of vitamin E and K analogs.

show abstract

Applications of cyclopropylboranes in organic synthesis. 1. A stereocontrolled route to substituted cyclopropanol derivatives

Abstract: thiobenzophenone-derived cycloadducts were obtained relative to the amount resulting from a trap with dimethyl fumarate. a fellowship, K.S. and H.B. to UCSB for fellowships, and O.W. to the Swiss National Fund for financial support during postdoctoral studies conducted at UCSB.

Cited by 52 publications

References 1 publication

Dimethylation and Hydrodechlorination ofgem-Dichlorocyclopropanes with Grignard Reagents Promoted by Fe(III) or Co(II) Catalyst

Dimethylation and Hydrodechlorination ofgem-Dichlorocyclopropanes with Grignard Reagents Promoted by Fe(III) or Co(II) Catalyst

Transition Metal‐Catalyzed Carbon−Carbon Bond Formation with Grignard Reagents − Novel Reactions with a Classic Reagent

Cobalt Carbonyl Induced Transformations of Alkynyl- and Propadienyl-cyclopropanes

Contact Info

Product

Resources

About