Organotrifluoroborates: Exploring the frontiers of organoboron chemistry. I. Lithium-halogen exchange of bromoaryltrifluoroborates and subsequent reaction with electrophiles. II. Stereoselective reduction of alkynylpinacolboronates to afford cis-alkenylpinacolboronates and potassium trifluoroborates via a hydroboration/protodeboronation sequence. III. Potassium acyltrifluoroborates: Synthesis and reactivity [electronic resource].

Ellis, Noel M.
278 p.
Chemistry, Organic.
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Mode of access: World Wide Web.
Boron-containing organometallics are unique for the variety of ways in which they can be synthesized, the relatively mild conditions under which they cross-couple, their atom economy, ease of handling, and low environmental impact. Recently, organotrifluoroborates have proven to be highly useful and robust surrogates of boronic acids and boronate esters in a number of frequently utilized chemical transformations.
One of the most highly utilized reactions for the formation of C-C bonds is the metal-halogen exchange reaction. However, the strong nucleophilicity and basicity of the metallating reagents precludes their use in the presence of tricoordinate organoboron reagents. We found that tetracoordinate potassium organotrifluoroborate salts could be used to circumvent this well-recognized problem.*
The production of stereodefined alkenyl organometallics is a goal of ever-increasing value owing to the ability of these organometallics to cross-couple with little if any erosion in stereochemical purity. Access to cis -alkenylboron derivatives is well precedented in the literature, but the vast majority of examples possess a conspicuous dearth of functional groups. As part of a growing program to create highly functionalized potassium organotrifluoroborates and apply them in the context of natural product synthesis, we developed a facile method for the stereospecific production of cis-alkenylboron compounds.*
Despite considerable development in the chemistry of acyl silanes and acylstannanes, the acylboron moiety has remained a mere curiosity until now. As "ate" complexes, acyltrifluoroborates lack the empty p orbital that lends to tricoordinate organoborons their high reactivity. These compounds are white, crystalline solids that display indefinite benchtop stability. Ab initio modeling has provided insight into many of the unique modes of reactivity that these unusual compounds possess.*
*Please refer to dissertation for diagrams.
Source: Dissertation Abstracts International, Volume: 70-06, Section: B, page: 3509.
Adviser: Marsha I. Lester.
Thesis (Ph.D.)--University of Pennsylvania, 2009.
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School code: 0175.
University of Pennsylvania.
Contained In:
Dissertation Abstracts International 70-06B.
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