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Synthesis and Reactions of Bicyclo[1.1.0]butanes

Walczak, Maciej A (2010) Synthesis and Reactions of Bicyclo[1.1.0]butanes. Doctoral Dissertation, University of Pittsburgh. (Unpublished)

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This dissertation describes methods for the synthesis of bicyclo[1.1.0]butanes and their reactions. The bicyclo[1.1.0]butyl skeleton was first assembled by intramolecular, amide directed Simmons-Smith cyclopropanation of propargyl amides and cyclopropenes. However, a more general approach applicable to the synthesis of amines, alcohol, esters, and amides was developed. This method is based on the generation of bicyclo[1.1.0]butyllithium from gem-dibromocyclopropanes via sequential transmetallation reactions with alkyllithium reagents and addition to electrophilic acceptors.Studies on the reaction of bicyclo[1.1.0]butanes were focused on thermal and metal-catalyzed transformations. Bicyclo[1.1.0]butanes activated by an aromatic group underwent highly chemo- and diastereoselective intramolecular pericyclic reactions under mild conditions. The outcome of these processes was controlled by the selection of the allylating reagents, and N-allyl amides gave exclusively formal ene products. On the other hand, cinnamyl amides participated in an intramolecular cycloaddition reaction. The postulated presence of radical in the mechanism of these reactions was supported by chemical and spectroscopic (ESR) studies.In the metal-catalyzed cycloisomerization reactions, an intramolecular cyclopropanation of allyl amides catalyzed by complexes of Rh(I) is described. These reactions proceeded via metal carbene intermediates, which were selectively generated by applying phosphine additives with different steric and electronic properties. Based on the mechanistic proposal, the synthesis of pyrroles from bicyclo[1.1.0]butanes was achieved using a Rh(I)/bidentate ligand catalytic system and hindered amides. Finally, cycloisomerization reactions of propargyl amides and ethers as well as electron-deficient bicyclo[1.1.0]butanes catalyzed by Pt(II) are described. These reactions proceeded via a series of carbene intermediates to give polycyclic nitrogen- and oxygen-containing heterocycles, which could be of utility in research and development.


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Item Type: University of Pittsburgh ETD
Status: Unpublished
CreatorsEmailPitt UsernameORCID
Walczak, Maciej Amaw50@pitt.eduMAW50
ETD Committee:
TitleMemberEmail AddressPitt UsernameORCID
Committee ChairWipf, Peterpwipf@pitt.eduPWIPF
Committee MemberDay, Billy Wbday@pitt.eduBDAY
Committee MemberWilcox, Craig Sdaylite@pitt.eduDAYLITE
Committee MemberNelson, Scott Gsgnelson@pitt.eduSGNELSON
Date: 29 January 2010
Date Type: Completion
Defense Date: 31 August 2009
Approval Date: 29 January 2010
Submission Date: 21 September 2009
Access Restriction: 5 year -- Restrict access to University of Pittsburgh for a period of 5 years.
Institution: University of Pittsburgh
Schools and Programs: Dietrich School of Arts and Sciences > Chemistry
Degree: PhD - Doctor of Philosophy
Thesis Type: Doctoral Dissertation
Refereed: Yes
Uncontrolled Keywords: bicyclo[1.1.0]butane; cycloisomerization reactions; pericyclic reactions; platinum; rhodium
Other ID:, etd-09212009-150816
Date Deposited: 10 Nov 2011 20:02
Last Modified: 15 Nov 2016 13:50


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