Date of Award
2018
Document Type
Honors Thesis (Open Access)
Department
Colby College. Chemistry Dept.
Advisor(s)
Dasan Thamattoor
Second Advisor
Jeffrey Katz
Abstract
Chloro(trimethylsilyl)carbene and chloro(trimethylstannyl)carbene were generated through photolysis of cyclopropanated phenanthrene precursors which were synthesized in two steps. The photolysis reactions were done in the presence of cis and/or trans-beta-methylstyrene. Though product peaks corresponding to the carbene-alkene adducts were observed in the GCMS, the yields were too low for their isolation and complete characterization. Density functional theory (DFT) calculations were performed on the stereoisomers of the precursor to Chloro(trimethylsilyl)carbene and the carbene itself. Surprisingly, Chloro(trimethylsilyl)carbene’s triplet state was found to be more stable than the singlet at this level of theory.
In a related project, (1-bromo-1a,9b-dihydro-1H-cyclopropa[l]phenanthren-1-yl)trimethylstannane, was synthesized in an effort to generate bicylopropylidene dimers via a coupling reaction using copper thiophene-2-carboxylate. Instead a cyclobutane derivative was obtained. Two mechanisms leading to the observed product are proposed: (a) rearrangement of the initially formed and expected dimer(s) and/or (b) dimerization of a dibenzocycloheptatraene (allene), formed directly from a cyclopropylidenoid, or through the generation and rearrangement of a cyclopropylidene. DFT calculations were also carried out to assess the relative stabilities of the bicylopropylidene dimers and the cyclobutane derivative.
Keywords
chlorosilylcarbene, chlorostannylcarbene, cyclopropylidene, copper-induced coupling, photolysis
Recommended Citation
Srour, Noura, "Silicon and tin substituted halocyclopropanes: approaches to new carbenes and strained cyclic allenes" (2018). Honors Theses. Paper 951.https://digitalcommons.colby.edu/honorstheses/951