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Date of Award

Spring 2012

Document Type

Restricted Thesis: Campus only access

Degree Name

Bachelor of Science

Department

Chemistry

First Advisor

Dr. William H. Myers

Abstract

Vinyl compounds undergo hydroboration when reacted with a solution of 9-BBN-H in THF. The borane compounds that form can be cross-coupled to (Z)-3-chloro-3-(3,4- dimethoxyphenyl)acrylaldehyde in the presence of PdCl2(dppf) catalyst, yielding a substituted enal product. One-pot reactions using styrene, 4-vinyl-1-cyclohexene, 1-hexene or vinyl- cyclohexane as the starting material all gave products in good yield and favorable diastereomeric ratio as confirmed by the NMR data.

Products were purified with column and/or flash chromatography as well as methanol/hexane extractions and characterized by 1D and 2D NMR, GC-MS, High Resolution Mass Spectrometry (HRMS), and IR. The importance of this reaction lies in the fact that the new bond that is created involves an sp3 carbon (from the former vinyl compound) connecting to an sp2 carbon (from the enal). Such cross-coupling is not unknown, but it is less common than Csp2-Csp2 coupling.1 Furthermore, good reactivity is observed with the vinyl chloride species despite the slower steps usually associated with chloride coupling reagents. Attempts were made, using cyclohexene, to cross-couple an internal alkene in this manner, but while there was evidence of the hydroboration step having occurred, there was no evidence of cross-coupled product found. In trying to expand the range of compounds that can be efficiently cross-coupled to chloroenals, terminal alkynes were also tested. Results indicated the formation of mixtures of products which were not easily separable. GC-MS data showed evidence for the expected cross-coupled product as well as for the analogous unsaturated product, suggesting the need for modifications in the synthesis to obtain the desired alkyne reactivity.

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