Chemo-, diastero-, and regioselective C-C and C-O bond formation via transition metal catalysis

The efficient stereoselective formation of C-C and C-O bonds remains a critical challenge in organic chemistry. The level difficulty of these bond formations increases dramatically when regio-, diastereo-, and chemoselectivity issues are present. In efforts to address such challenges, this thesis summarizes three successful strategies to develop highly stereoselective C-C and C-O bond formation reactions: 1) the first strategy outlines the direct metallation and subsequent chemo- and regioselective cross-coupling of benzylic sp3-hybridized C-H bonds (pKa values \u3e34) to form C- bonds via palladium catalyzed deprotonative cross-coupling process (DCCP), 2) the second strategy outlines the application of 1,1-heterobimetallic borozinc reagents in the diastereoselective C- bond-forming reactions, and 3) the third strategy outlines the use of transition metal-catalysis in the highly chemo- and diastereoselective C−O bond formation via vanadium catalyzed directed epoxidation. Chapters 1 and 2 summarize a program that we have recently initiated in our laboratory known as deprotonative cross-coupling process (DCCP). DCCP is the reversible in situ deprotonation of weakly acidic sp3-hybridized C-H bonds under mild conditions, which are then catalytically cross-coupled with aryl electrophiles under palladium catalysis. Chapters 3 and 4 summarize the potential usefulness of 1-alkenyl-l,l-heterobimetallics in the stereoselective C-C bond formations in organic synthesis. Our group reported a practical generation of 1,1-heterobimetallics from air-stable B(pin)-substituted alkynylboronate esters and demonstrated their utility in a variety of one-pot transformations to provide boron-substituted allylic alcohols, dienols, α-hydroxy ketones, and α-dihydroxy ketones with high diastereoselectivity. More applications of these reagents are also explored in Chapters 3 and 4