Trimethylene substituted

In 1909, Patemo and Chieffi noted that mixtures of tri- or tetra-substituted olefins and aldehydes formed trimethylene oxides when exposed to sunlight. Biichi later repeated Patemo s experiments by irradiating 2-methyI-2-butene in the presence of benzaldehyde, butyraldehyde, or aeetophenone and rigorously purifying and identifying the resulting products. The reaction thus bears the name of its two primary pioneers and has come to represent any photo-catalyzed [2 + 2] electrocyclization of a carbonyl and an alkene. 

The macrocyclic bis(oximato)borates 130-131 and its tetramethylene analogue 132 are derivatives of the bisborylated dioxime complexes discussed above, in which one of the OBR2O groups has been substituted by a trimethylene or tetramethylene unit, respectively (Fig. 35). 

Synthesis. The 2-phenyM,3,2-diazaboracyclohexane ring system (1) was selected as the starting material in this study because (1) it is prepared easily and in high yield by a three step synthesis from BCI3 (2) the N-H bonds are potential sites for deprotonation and substitution reactions and (3) the trimethylene bridge enhances the rigidity of the N-B-N backbone which should prevent cyclization upon thermolysis of an appropriate precursor. 

Actually, C-substituted cyclams are more common in the coordination chemistry of Co, with ligating pendent groups typically attached to the trimethylene ring C atoms. The synthetic... 

A direct observation of a triplet state of substituted trimethylene biradical has recently been claimed.84) This is in good agreement with the prediction 104,105) that the lowest excited state of cyclopropane will have an energy minimum at a geometry in which one C—C bond is broken. 

N. Tanigaki, H. Masude, and K. Kaeriyama, Substituted poly(p-phenylene)s prepared from 2,5-diheptylbenzene-l,4-bis(trimethylene boronate), Polymer, 38 1221-1226, 1997. 

Y-conjugated derivatives of trimethylene methane (87) and a,a -acetonediyl dianions (88) give good yields of expected mono- and di-substitution products on... 

A theoretical ab initio study of the interconversion of isobutonium ions has been carried out. The 1,1-trimethylene-l//-azulenium ion (202) has been prepared and its chemical behaviour has been shown to be different from that of its three-membered ring homologue. The solvolysis of l-[trans-2-(m- or / -substituted phenyl)... 

The formation of a-substituted thiolanes 203 in 40-70% yields was observed by reactions of trimethylene sulfoxide with organomagnesium compounds (Eq. 49). ... 

An interesting rearrangement of thioureas leading to tetrahydro-1,3-thiazines has been reported by Tisler,297,298 who found that 1-trimethylene-3-aryl-2-thioureas undergo facile conversion to 150 in concentrated HC1. The same products (150) could also be prepared by treating the appropriately substituted thiourea with 1,3-dibromo-propane.298... 

Leaving the halogen and methyl substitution products of trimethylene,there can be Been the possibility of countless cyclopropane compounds of different types obtained by substitution of the hydrogen... 

In alkyl or aryl carbonates, the problem of conformation is repeated twice on the two C—O bonds linked to the same central atom. It was stated generally177 that in such cases the common conformation of the monofunctional compound is repeated in either moiety. This holds with a few exceptions and/or modifications when the molecule is strongly crowded. This is also the case of carbonates. According to this rule, the sp,sp conformation (74) was found in carbonates in two independent investigations. In the first178 para-substituted phenyls were used in place of R the second started from the fixed conformation of trimethylene carbonate and besides the dipole moment exploited also the Kerr constant179. 

If the carboxyl group be next attacked by MgR X, the following change takes place, resulting in a substituted trimethylene glycol ... 

The cyclopropane radical cation can be prepared by y-radiolysis in rigid matrices its ESR spectrum at 4.2 K shows evidence for static Jahn-Teller distortion, resulting in a structure of the trimethylene (2Aj) type [294, 295], Irradiation of several methyl substituted derivatives at 77 K gave rise to a family of radical cations of the same structure type [293], which had been previously identified on the basis of CIDNP results [229, 230]. We begin with a discussion of the CIDNP investigations, since they preceded the ESR studies of all species but the prototype. 

The [10 11] methano[3 2]paracyclophane system (108) [229] appears less strained than 107 yet more restricted than diphenylcyclopropane. The CIDNP effects observed are closer to that of ds-diphenylcyclopropane than to that of 107. Obviously, a large fraction of the strain inherent in 107 is relieved by substituting a trimethylene bridge for one of the cyclopropane moieties [229],... 

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