four-membered ring

The C has the structure in which a four-membered ring is surrounded by four six-membered rings.

X-ray structural determinations revealed that 1a, 1c and 2 contain four-membered rings.

The only difference is that the four-membered ring ground state is planar and not bent.

It is an alkene and it contains a reactive four-membered ring.

This ketene then dimerizes to form a four-membered ring with two ketone groups.

This approach relies on acyl transfer in the Mumm rearrangement to form the four-membered ring.

The mirror plane of the crystal contains the atoms in the four-membered rings and the other oxygen atoms.

The four-membered ring carbon resonances occur in the 180–190 ppm range and are attributed to the cyclobutenediylium character of this structure.

Lactones with three- or four-membered rings (α-lactones and β-lactones) are very reactive, making their isolation difficult.

A curious behaviour was observed with o-chloroiodobenzene, which gave activation of the C—Cl bond with four-membered ring formation.

The four-membered ring is tightly folded, and bond angles in the vicinity of this ring indicate considerable strain.

The Li atoms and the ipso carbons of the phenyl rings form a planar four-membered ring.

Thietane is a heterocyclic compound containing a saturated four-membered ring with three carbon atoms and one sulfur atom.

All of this enormous family are derived from a b-lactam structure: a four-membered ring in which the b-lactam bond resembles a peptide bond.

For example: to draw a four-membered ring select the cyclobutane icon on the icon palette and press the LM in the drawing area.

As a chelating ligand, 1,1-bis(diphenylphosphino)methane forms a four-membered ring with the constituents MPC.

With heating, the central phosphorus/sulfur four-membered ring can open to form two reactive dithiophosphine ylides (R-PS).

The four-membered ring in α-pinene 1 makes it a reactive hydrocarbon, prone to skeletal rearrangements such as the Wagner-Meerwein rearrangement.

The folded geometry of the four-membered ring in these adducts apparently determines the stabilities of the epimers, and the proton–proton vicinal coupling constants.

Both 8 and 9 are stable compounds containing an intact four-membered ring, and these compounds helped greatly in identifying this important component of the pinene skeleton.

A dioxetane or dioxacyclobutane is an organic compound with formula COH, whose backbone is a four-membered ring of two oxygen atoms and two carbon atoms.

Oxetane, or 1,3-propylene oxide, is an heterocyclic organic compound with the molecular formula CHO, having a four-membered ring with three carbon atoms and one oxygen atom.

In the conversion, the silver first becomes sulfided, and the resulting AgS catalyzes the conversion of the SN into the four-membered ring SN, which readily polymerizes.

Therefore, when there is a choice, a preference for five-membered rings is observed: four-membered rings are too strained, and collisions with carbons six or more atoms away in the chain are infrequent.

In the presence of a chiral tertiary amine complex, several sulfenes could be trapped with trichloroacetaldehyde (chloral) in a catalytic asymmetric synthesis of β-sultones (four-membered ring sulfonate esters).