Bicyclo[n.1.0]alkenes

Billups, W. E.; Haley, Michael M.; Lee, Gon-Ann

doi:10.1021/cr00095a011

Cited by 66 publications

(28 citation statements)

References 39 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…It showed that one of the terminal triple bonds had been incorporated in a way that was regioisomeric to normal, the resulting bowl shaped ligand bearing the metal on its convex face. Remarkably, the bond lengths and (dihedral) angles around the metalated diene unit in this (formally) anti-Bredt [51] molecule are unexceptional. The relatively large chemical shifts of H a [d = 3.93 (d, J = 7.9 Hz)] and H b [d = 3.76 (dd, J = 7.8, 5.5 Hz)] corroborate the stereochemical assignments of 66 (syn) and 67 (anti).…”

Section: Nàh Activation Reactionsmentioning

confidence: 89%

Cobalt‐Mediated [2+2+2] Cycloaddition versus CH and NH Activation of Pyridones and Pyrazinones with Alkynes: An Experimental Study

Aubert

Betschmann

Eichberg

et al. 2007

Chemistry A European J

View full text Add to dashboard Cite

The reactivity of a range of pyridone and pyrazinone derivatives towards alkynes in the presence of cyclopentadienylcobaltbis(ethene) has been investigated. Depending on the nature of the substrates, [2+2+2]- or [2+2] cycloaddition, C-H, or N-H activation may occur. In the case of pyridones, the first three predominated with N-protected derivatives, whereas substrates containing N-H bonds followed an N-H activation pathway. The [2+2+2] cycloaddition of an N-butynylisoquinolone was applied successfully to the total synthesis of anhydrolycorinone. Pyrazinone substrates showed similar patterns of reactivity.

show abstract

Section: Nàh Activation Reactionsmentioning

confidence: 89%

Cobalt‐Mediated [2+2+2] Cycloaddition versus CH and NH Activation of Pyridones and Pyrazinones with Alkynes: An Experimental Study

Aubert

Betschmann

Eichberg

et al. 2007

Chemistry A European J

View full text Add to dashboard Cite

show abstract

“…Formation of furans only by their 13 C-NMR spectra but also by their 29 Sichemical shifts which were found at δ ϭ 11.5Ϫ13.3 for oxa-analogous to 6 has been reported for Rh 2 (OAc) 4 -mediated reactions of (1-oxopent-4-yn-1-yl)diazoacetates [12] and -disilines 3a,c,e and at 30.9Ϫ38.0 for dihydrooxasiloles 5a,c,e. azoketones [11] as well as for a (N-propargylcarbamoyl)di-different products.…”

Section: Resultsmentioning

confidence: 72%

“…Table 1 also suggests that the size of the alkyl groups presumably too strained to be isolated at room temperature; in the all-carbon bicyclo[n.1.0]alkene case, at least four attached to silicon has an effect on the product pattern. We had assumed originally that the change from SiMe 2 (1a) to atoms in the larger bridge would be necessary [29] . For bicyclic cyclopropenes which are structurally related to 9, such as SiiPr 2 (1bϪe) and SitBu 2 (1f,g) in general would increase the efficiency of the intramolecular carbenoid reaction and bicyclo[3.1.0]hex-1(6)-enes [29,30] and bicyclo[3.1.0]hexa-3,5-dien-2-ones [31] , the cyclopropene-to-vinylcarbene isomeri-in particular would favor the formation of five-rather than six-membered rings by the action of the ThorpeϪIngold zation [22] leading to the six-membered, endocyclic carbene takes place very easily [32] .…”

Section: Resultsmentioning

confidence: 99%

“…Column chromatography was performed under hydrostatic conditions (silica gel Si 60, 0.063Ϫ0.2 mm, Macherey-Nagel; silica gel Si 60 silanized, 0.063Ϫ0.2 mm, Merck; neutral aluminum oxide 90, activity I, Merck). [21] , but the opposite is observed when the Cu- 29 Si-NMR spectra, and the solvent signal for the 13 OTf-catalyzed reactions of 1b and 1d are compared.…”

Section: Methodsmentioning

confidence: 92%

See 1 more Smart Citation

Intramolecular Copper- and Rhodium-Mediated Carbenoid Reactions of α-(Propargyloxy)silyl-α-diazoacetates

Gettwert¹,

Krebs²,

Maas³

1999

Eur. J. Org. Chem.

View full text Add to dashboard Cite

Copper(I) triflate catalyzes the transformation of α‐[(2‐alkynyl)oxy]silyl‐α‐diazoacetates 1a–g into 1,2‐bis(2,5‐dihydro‐1,2‐oxasilol‐4‐yl)ethenes 2 and/or 2H‐1,2‐oxasilines 3. With rhodium(II) perfluorobutyrate as catalyst, 1a–e furnish only 3 but no 2. Bicyclic 2‐methoxyfurans 6 are formed when 1a,c,e (containing terminal alkyne functions) are treated with catalytic amounts of copper(I) chloride. The experimental observations are explained in terms of metal‐mediated intramolecular cyclopropenation and subsequent metal‐assisted ring‐opening of the strained bicyclic cyclopropene leading to vinylcarbene‐metal complexes. An unusual autoxidation of 2H‐1,2‐oxasilines 3a,c,e is also described.

show abstract

“…Their syntheses, highly strained structures and high reactivities have widely attracted the attention of both theoretical and experimental chemists since the pioneering work of Bredt [1][2][3][4][5] . Bicyclo[1.1.0]but-1(2)-ene (BBE, E ¼ C, Fig.…”

mentioning

confidence: 99%

A heavy analogue of the smallest bridgehead alkene stabilized by a base

2014

View full text Add to dashboard Cite

Bicyclo[1.1.0]but-1(2)-ene (BBE), one of the smallest bridgehead alkenes and C 4 H 4 isomers, exists theoretically as a reactive intermediate, but has not been observed experimentally. Here we successfully synthesize the silicon analogue of BBE, tetrasilabicyclo[1.1.0]but-1(2)-ene (Si 4 BBE), in a base-stabilized form. The results of X-ray diffraction analysis and theoretical study indicate that Si 4 BBE predominantly exists as a zwitterionic structure involving a tetrasilahomocyclopropenylium cation and a silyl anion rather than a bicyclic structure with a localized highly strained double bond. The reaction of base-stabilized Si 4 BBE with triphenylborane affords the [2 þ 2] cycloadduct of Si 4 BBE and the dimer of an isomer of Si 4 BBE, tetrasilabicyclo[1.1.0]butan-2-ylidene (Si 4 BBY). The facile isomerization between Si 4 BBE and Si 4 BBY is supported by theoretical calculations and trapping reactions. Structure and properties of a heavy analogue of the smallest bridgehead alkene are disclosed.

show abstract

Bicyclo[n.1.0]alkenes

Cited by 66 publications

References 39 publications

Cobalt‐Mediated [2+2+2] Cycloaddition versus CH and NH Activation of Pyridones and Pyrazinones with Alkynes: An Experimental Study

Cobalt‐Mediated [2+2+2] Cycloaddition versus CH and NH Activation of Pyridones and Pyrazinones with Alkynes: An Experimental Study

Intramolecular Copper- and Rhodium-Mediated Carbenoid Reactions of α-(Propargyloxy)silyl-α-diazoacetates

A heavy analogue of the smallest bridgehead alkene stabilized by a base

Contact Info

Product

Resources

About