Synthesis of halogenated bicyclic molecules involving Prins cyclization from aldehydes and non-conjugated diene alcohol

The reactions of aldehydes and a non-conjugated alcohol, (E)-octa-3,7-dien-1-ol, in the presence of halogen-containing reagents afforded the corresponding halogenated bicyclic molecules in good yields. The optimization, scope and limitations of the reactions as well as scale-up reactions have been examined. Quantum chemical calculations helped clarify the microscopic mechanism of a key reaction process, the introduction of a Cl atom to a bicyclic carbocation.

Synthesis of Multi-Substituted Bicycloalkyl Boronates: An Intramolecular Coupling Approach to Alkyl Bioisosteres

<p>Bicyclic hydrocarbons, bicyclo[1.1.1]pentanes (BCPs) in particular, play an emerging role as saturated bioisosteres in pharmaceutical, agrochemical, and material chemistry. Taking advantage of strain release strategies, prior synthetic studies have featured the synthesis of bridgehead-substituted (C1, C3) BCPs from [1.1.1]propellane. This work describes a novel approach to accessing multi-substituted BCPs via a new type of intramolecular cyclization. In addition to the C1, C3-disubstituted BCPs, this method also enables the construction of yet underexplored tri-substituted (C1, C2 and C3) BCPs from readily accessible cyclobutanones. The broad generality of this cyclization is examined through synthesis of a variety of caged bicyclic molecules, ranging from [1.1.1] to [3.2.1] scaffolds. The modularity afforded by the pendant bridgehead Bpin resulted from the cyclization is demonstrated via several downstream functionalizations, highlighting the ability of this approach for programmed and divergent synthesis of multi-substituted bicyclic hydrocarbons.<br></p>

Synthesis of Multi-Substituted Bicycloalkyl Boronates: An Intramolecular Coupling Approach to Alkyl Bioisosteres

<p>Bicyclic hydrocarbons, bicyclo[1.1.1]pentanes (BCPs) in particular, play an emerging role as saturated bioisosteres in pharmaceutical, agrochemical, and material chemistry. Taking advantage of strain release strategies, prior synthetic studies have featured the synthesis of bridgehead-substituted (C1, C3) BCPs from [1.1.1]propellane. This work describes a novel approach to accessing multi-substituted BCPs via a new type of intramolecular cyclization. In addition to the C1, C3-disubstituted BCPs, this method also enables the construction of yet underexplored tri-substituted (C1, C2 and C3) BCPs from readily accessible cyclobutanones. The broad generality of this cyclization is examined through synthesis of a variety of caged bicyclic molecules, ranging from [1.1.1] to [3.2.1] scaffolds. The modularity afforded by the pendant bridgehead Bpin resulted from the cyclization is demonstrated via several downstream functionalizations, highlighting the ability of this approach for programmed and divergent synthesis of multi-substituted bicyclic hydrocarbons.<br></p>

Photochemical rearrangement reactions of bicyclic molecules that contain a cyclopropane ring

Our theoretical observations indicate that for [2.1.0], [3.1.0], [4.1.0], and [5.1.0] molecules, the quantum yields of the tautomeric keto forms are larger than those of the corresponding enol isomers.

Rhodium(i)-catalyzed asymmetric [4 + 2] cycloaddition reactions of 2-alkylenecyclobutanols with cyclic enones through C–C bond cleavage: efficient access totrans-bicyclic compounds

We report a rhodium-catalyzed asymmetric formal intermolecular [4 + 2] cycloaddition reaction of 2-alkylenecyclobutanols with α,β-unsaturated cyclic ketones leading to synthetically usefultrans-bicyclic molecules.

Triazene derivatives of (1,x)-diazacycloalkanes. Part VII. Synthesis of a series of 1-aryl-2-[3-(3-[2-aryl-1-diazenyl]-1,3-diazepan-1-ylmethyl)-1,3-diazepan-1-yl]-1-diazenes from the reaction of diazonium salts with mixtures of formaldehyde and 1,4-diaminobutane

A new series of bistriazenes, the 1-aryl-2-[3-(3-[2-aryl-1-diazenyl]-1,3-diazepan-1-ylmethyl)-1,3-diazepan-1-yl]-1-diazenes (8), has been synthesized from the reaction of diazonium salts with a mixture of 1,4-diaminobutane and formaldehyde. All new compounds of series 8 have been characterized by IR and NMR spectroscopy, and the elemental composition of selected examples has been verified by elemental analysis. The connectivity of the series has been unequivocally determined by X-ray crystallography. The new bistriazenes are important because the structure contains the novel saturated heterocycle, 1,3-diazepane. The general conclusion of this study is that alkanediamines with three or four carbon atoms in the spacer link between the nitrogen atoms give rise to the linear bicyclic molecules of type 2, in contrast to the case of ethylenediamine (two carbon atoms in spacer link), which affords molecules of type 3, which exemplify the cage structure of type 1.Key words: diazonium salt, triazene, bistriazene, diazepane, formaldehyde, nuclear magnetic resonance.