Cobalt-catalyzed deoxygenative triborylation of allylic ethers to access 1,1,3-triborylalkanes

Abstract

Polyborylated organic compounds have been emerging as versatile building blocks in chemical synthesis. Here we report a selective cobalt-catalyzed deoxygenative 1,1,3-triborylation reaction of allylic ethers with pinacolborane to prepare 1,1,3-triborylalkane compounds. With naturally abundant and/or synthetic cinnamic methyl ethers as starting materials, we have achieved the synthesis of a variety of 1,1,3-triborylalkanes (25 examples). The synthetic utility of these 1,1,3-triborylalkanes is demonstrated through site-selective allylation, protodeborylation, and consecutive carbon-carbon bond-forming reactions. Mechanistic studies including deuterium-labeling and control experiments suggest that this 1,1,3-triborylation reaction proceeds through initial cobalt-catalyzed deoxygenative borylation of allylic ethers to form allylic boronates followed by cobalt-catalyzed 1,1-diborylation of the resulting allylic boronates.

Stereoselective Diels–Alder Reactions of gem-Diborylalkenes: Toward the Synthesis of gem-Diboron-Based Polymers

“…In recent years, gem -diboryl compounds 2 and 3′ have been widely adopted as coupling partners in synthetic chemistry. 11 , 20 For example, gem -diborylalkenes 2 have served as building blocks for Suzuki–Miyaura cross-coupling, nucleophilic partners, reduction approaches, Michael additions, 21 radical chemistry, 22 and other reactions. 13 , 23 …”

Stereoselective Diels-Alder Reactions of gem-Diborylalkenes: Toward the Synthesis of gem-Diboron-Based Polymers via ROMP

“…8 Therefore, over the last decade, much effort has been expended to synthesize new functionalized classes of polyboronates, which have been shown to be excellent building blocks for the modular construction of new compounds. [9][10][11][12] Among polyboron-containing structural motifs, (unsymmetrical) 13 gem-diboron derivatives (2, 3') are a well-known emerging class with good potential for novel synthetic applications (Figure 1A). [14][15][16][17] The special properties and structures of bisnucleophile gem-diboryl compounds 2, 3' (termed geminated organodimetallics) 18,19 have attracted increasing attention from synthetic chemists, particularly in constructing C-C/ C-heteroatom bonds.…”

“…In recent years, gem-diboryl compounds 2, 3' have been widely adopted as coupling partners in synthetic chemistry. 11,20 Despite the fact that organoborons 1, 1' (Figure 1A) have been applied in many fields including materials, polymers [21][22][23][24] I (Figure 1B), drugs, and in industry, gem-diboryl units 2, 3' have seldom been employed in these fields, e.g., polymer II (Figure 1C). To this end, we contend that a new paradigm of research is needed to complementarily propel this gem-diboryl class of compounds to reach the same application level as their mono-boron analogs.…”

Stereoselective Diels-Alder Reactions of gem-Diborylalkenes: Toward the Synthesis of gem-Diboron-Based Polymers via ROMP

“…8 Therefore, over the last decade, much effort has been expended to synthesize new functionalized classes of polyboronates, which have been shown to be excellent building blocks for the modular construction of new compounds. [9][10][11][12] Among polyboron-containing structural motifs, (unsymmetrical) 13 gem-diboron derivatives (2, 3') are a well-known emerging class with good potential for novel synthetic applications (Figure 1A). [14][15][16][17] The special properties and structures of bisnucleophile gem-diboryl compounds 2, 3' (termed geminated organodimetallics) 18,19 have attracted increasing attention from synthetic chemists, particularly in constructing C-C/ C-heteroatom bonds.…”

“…In recent years, gem-diboryl compounds 2, 3' have been widely adopted as coupling partners in synthetic chemistry. 11,20 Despite the fact that organoborons 1, 1' (Figure 1A) have been applied in many fields including materials, polymers [21][22][23][24] I (Figure 1B), drugs, and in industry, gem-diboryl units 2, 3' have seldom been employed in these fields, e.g., polymer II (Figure 1C). To this end, we contend that a new paradigm of research is needed to complementarily propel this gem-diboryl class of compounds to reach the same application level as their mono-boron analogs.…”