Selective reactions of alkylated 1-acyl-2,2-dibromocyclopropanes

Sydnes, Leiv Kr.; Skattebøl, Lars

doi:10.1016/s0040-4039(00)91081-5

Cited by 8 publications

(5 citation statements)

References 3 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…In this regioselective and stereoselective reaction, epoxidation occurs exclusively at the conjugated double bond with the formation of the epoxi-carvone (111) indicated. The reaction of dichlorocarbene with carvone, in our hands, is not regioselective as the attack of the carbene occurs at both double bonds (IV), whereas the dibromocarbene adduct (V) is formed regioselectively (5).…”

Section: Introductionmentioning

confidence: 55%

Structural studies on the dichlorocarbene adducts with (−)-R-carvone. I. The crystal structures of [1R, 4R, 6R, 9R]-7,7-dichloro-1-methyl-4-[2′,2′-dichloro-1′-methyl- cyclopropyl]-bicyclo[4.1.0]-heptan-2-one and [1R, 4R, 6R, 9S]-7,7-dichloro-1-methyl-4-[2′,2′-dichloro-1′-methylcyclopropyl]-bicyclo[4.1.0]-heptan-2-one

Zukerman-Schpector¹,

Castellano²,

Oliva³

et al. 1984

Can. J. Chem.

View full text Add to dashboard Cite

Structural studies on the dichlorocarbene adducts with (-)-R-carvone. I. The crystal structures of [lR, 4R, 6R, 9R]-7,7-dichloro-l-methyl-4-[2',2'-dichloro-lr-methyl- Quimica, Universidade Fecleral de Srio Carlos, Caixa Posfal 676, 13.560-Srio Carlos-SP, Brazil Received May 25, 1983 J. ZUKERMAN-SCHPECTOR, E. E. CASTELLANO. G. OLIVA, TIMOTHY JOHN BROCKSOM, and ELISABETE TEREZINHA CANEVAROLO. Can. J. Chem. 62, 570 (1984).The crystal structures of the title compounds have been determined from diffractometric X-ray data and refined by full-matrix least-squares to final R factors of 0.047 and 0.060 from 830 and 620 independent reflections above background, respectively. The space group and the number of molecules peaunit cell are the same in both cases: P2,2,2, and Z la forme R. Les moltcules, qui sont produites simultantment par la mCme rtaction chimique, ont essentiellement la mCme configuration sauf en ce qui a trait a la position des atomes de chlore en C-l 1 (dans le cas de la forme S) et a celle du groupe C-10 (dans le cas de la forme R). Cette difftrence conduit a un entassement moltculaire des structures complktement different. Dans chaque compost, les deux cycles cyclopropanes sont en position cis avec un angle dikdre identique dc 77,0°.

show abstract

Section: Introductionmentioning

confidence: 55%

Structural studies on the dichlorocarbene adducts with (−)-R-carvone. I. The crystal structures of [1R, 4R, 6R, 9R]-7,7-dichloro-1-methyl-4-[2′,2′-dichloro-1′-methyl- cyclopropyl]-bicyclo[4.1.0]-heptan-2-one and [1R, 4R, 6R, 9S]-7,7-dichloro-1-methyl-4-[2′,2′-dichloro-1′-methylcyclopropyl]-bicyclo[4.1.0]-heptan-2-one

Zukerman-Schpector¹,

Castellano²,

Oliva³

et al. 1984

Can. J. Chem.

View full text Add to dashboard Cite

show abstract

“…Nevertheless, conventional approaches have not enabled access to a broad diversity of “parent” acyl BCBs bearing complex or densely functionalized R groups (see 1 ); in many cases, such derivatives would require highly elaborate or intractable synthetic precursors. Examples of BCB ketones are particularly scarce with only a handful (e.g., R=phenyl; methyl; isopropyl) reported to date.…”

Section: Methodsmentioning

confidence: 99%

Structurally Diverse Acyl Bicyclobutanes: Valuable Strained Electrophiles

Schwartz

Zhang

Attard

et al. 2020

Chemistry A European J

View full text Add to dashboard Cite

Bicyclo[1.1.0]butanes (BCBs) are highly strained carbocycles that have emerged as versatile synthetic tools, particularly for the construction of functionalized small molecules. This work reports two efficient pathways for the rapid preparation of over 20 structurally diverse BCB ketones, encompassing simple alkyl and aryl derivatives, as well as unprecedented amino acid, dipeptide, bioisostere, and bifunctional linchpin reagents currently inaccessible using literature methods. Analogues are readily forged in two steps and in high yields from simple carboxylic acids or through unsymmetrical ketone synthesis beginning with a convenient carbonyl dication equivalent. The utility of this novel toolbox of strained electrophiles for the selective modification of proteinogenic nucleophiles is highlighted.

show abstract

“…[8][9][10][11] We now report the reactions of amides (5) and (6) with methyl-lithium, when by varying the conditions we observe both reduced and carbenic products. Thus intramolecular insertions into carbon-hydrogen bonds or additions to carboncarbon double bonds have been observed leading, for example, to bicyclo[l.l.0]butanes (Scheme 2) or to the extremely reactive hydrocarbon (3) (Scheme 3).…”

Section: Rp: R'mentioning

confidence: 99%

“…Few reactions of 1,l-dibromocyclopropanes containing other functional groups such as esters, ketones, or acids, which might intercept either the alkyl-lithium or the intermediate carbenoid, have been described, and in these cases the usual products are those formed by reduction, such as cyclopropanes and monobromocyclopropanes. [8][9][10][11] We now report the reactions of amides (5) and ( 6) with methyl-lithium, when by varying the conditions we observe both reduced and carbenic products. The acid (7) has been obtained by Stein @ by reaction of methyl methacrylate with dibromocarbene (generated from PhHgCBr, or CHBr,-KOBut), followed by hydrolysis.…”

Section: Rp: R' (2) Schemementioning

confidence: 99%

The reaction of 1,1-dibromocyclopropanecarboxamides with methyllithium

Baird¹,

Baxter²

1979

J. Chem. Soc., Perkin Trans. 1

View full text Add to dashboard Cite

upon Tyne, Newcastle upon Tyne NE1 7RUOn reaction with one equivalent of methyl-lithium at below -60 "C followed by aqueous quenching, the dibromoamides (5) and (6) were reduced to monobromides (10) and (9). An intermediate could be partially trapped as a mono-deuteride (1 5) by quenching with D20 at low temperature, or as (14) by addition of benzadehyde, but could not be trapped by addition of Me,SiCI or CO, ; however, quenching with D 2 0 after the reaction solution had been warmed to 35 'C led to (10) with no deuterium incorporation. The source of the proton in this last reaction was the solvent, ether. Treatment of (5) with 2 mot equiv. MeLi at -60 "C also led after low-temperature aqueous quenching to (10) ; if the temperature was rapidly raised to 35 'C two products, (20) (major) and (19) (minor), were isolated after quenching. If, however, (5) was treated with 1 mol equiv. MeLi at -60 "C, followed by very slow addition of a second mol equiv. at 35', (1 9) was the major product. The monobromide (1 0) is an intermediate in both these reactions, and indeed leads to (19) and (20) in similar proportions to those from (5) when treated with 1 equiv. MeLi either rapidly or dropwise at 25-35 "C; reaction of (9) with 1 equiv. MeLi leads, however, to the ketone (11 ; X = Me). A second (presumed) diastereoisomer of (14) was also obtained but this could not be effectively separated from a third product,. Compound (14) was unusual in that restricted rotation led t o four doublets in the n.m.r. spectrum for the isopropyl methyl groups, as well as two isopropyl-CH signals. Published on 01 January 1979. Downloaded by UNIVERSITY OF NEBRASKA on 16/09/2013 13:36:45.* The reaction is more rapid in the presence of TMEDA, being complete in ca. 24 h at 35 "C in ether. TMEDA is known to dramatically increase the rate of metallation by alkyl-lithiums.38

show abstract

Selective reactions of alkylated 1-acyl-2,2-dibromocyclopropanes

Cited by 8 publications

References 3 publications

Structurally Diverse Acyl Bicyclobutanes: Valuable Strained Electrophiles

The reaction of 1,1-dibromocyclopropanecarboxamides with methyllithium

Contact Info

Product

Resources

About