Selective Deprotonation in Acyclic Systems (Chemistry)

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The construction of carbon-carbon bonds remains as a key challenge in the construction of new organic molecules. Implicit in this challenge is the achievement of selectivity in forming the new bond. This research will investigate new reaction pathways for the selective introduction of carbon-carbon bonds into acyclic systems. The desired selectivity will be sought in the selective formation of carbanions via a heteroatom-assisted deprotonation. New reaction types which will be studied include: (1) the direct beta-lithiation of vinyl and dienyl ethers; (2) the diastereoselective deprotonation of acyclic protons in systems other than sulfoxides; (3) the intramolecular addition of unstabilized carbanions to ketones and aldehydes. The products which result from these reactions are often unique structures which will lend themselves to numerous stereoselective transformations. For example, the first class of asymmetric dienes to exhibit complete pi-face selectivity in the Diels-Alder reaction will be available through the directed deprotonation of dienyl ethers. Whenever possible models will be proposed and tested in an effort to delineate the exact effect that nearby heteroatoms have on the selectivity of deprotonation. Based on this knowledge, heteroatom-assisted deprotonations can be rationally extended to new systems rendering it an even more powerful method for selective bond construction.