Catalytic Conjunctive Coupling of Carboxylic Acid Derivatives with 9‐BBN‐Derived Ate Complexes

Abstract

β‐Boryl carbonyl compounds are produced by a Ni‐catalyzed cross‐coupling of vinylboron “ate” complexes and acid chloride or acid anhydride electrophiles. The reactions are efficient, being complete in as little as two minutes, and can be applied to a broad range of substrates.

Enantioselective Synthesis of Tertiary β‐Boryl Amides by Conjunctive Cross‐Coupling of Alkenyl Boronates and Carbamoyl Chlorides

“…As an alternative route to the assembly of tertiary β‐boryl carbonyls, we considered enantioselective conjunctive cross‐coupling [9] between alkenylboron ate complexes ( C , Scheme 1c) and carboxylic acid‐based electrophiles ( D ), by a reaction that employs acyl palladium complexes [10] to promote a 1,2‐metallate shift [11] . While enantioselective conjunctive cross‐coupling has been accomplished with aromatic, olefinic, and aliphatic electrophiles, cross‐coupling with carbonyl derivatives has only been accomplished in a racemic fashion and uses trialkylborane‐derived substrates [12] . Development of an enantioselective process that operates with boronic ester derivatives faces several distinct challenges.…”

“…[11] While enantioselective conjunctive cross-coupling has been accomplished with aromatic, olefinic, and aliphatic electrophiles, cross-coupling with carbonyl derivatives has only been accomplished in a racemic fashion and uses trialkylborane-derived substrates. [12] Development of an enantioselective process that operates with boronic ester derivatives faces several distinct challenges. First, carbonyl electrophiles are known to directly acylate the pinacol oxygen of four-coordinate boron ate complexes.…”

Stereospecific 1,2‐Migrations of Boronate Complexes Induced by Electrophiles

“…Morken subsequently extended the scope of these nickelcatalyzed conjunctive cross-couplings to other electrophiles, including alkyl halides and acid chlorides. [41] Scheme 13. Catalytic conjunctive cross-coupling reactions enabledb ypalladium-induced 1,2-migration.R M = Migratinggroup.…”

Total Synthesis of the Spliceosome Modulator Pladienolide B via Asymmetric Alcohol‐Mediated syn‐ and anti‐Diastereoselective Carbonyl Crotylation

“…Treatment of the hydroxy acid with tert ‐butyldimethylsilyl chloride results in silylation of both the C1 carboxylic acid and C3 hydroxyl groups. Addition of methanolic K 2 CO 3 to the reaction mixture results in concomitant cleavage of the silyl ester and the C7 acetate [25] to furnish the C6‐C7 diol, Fragment C . Under Yamaguchi conditions, Fragment C and Fragment D undergo esterification to form compound 5 despite the presence of the unprotected C7 hydroxyl [17, 26] .…”

“…Treatment of the hydroxy acid with tert-butyldimethylsilyl chloride results in silylation of both the C1 carboxylic acid and C3 hydroxyl groups. Addition of methanolic K 2 CO 3 to the reaction mixture results in concomitant cleavage of the silyl ester and the C7 acetate [25] to furnish the C6-C7 diol, Fragment C. Under Yamaguchi conditions, Fragment C and Fragment D undergo esterification to form compound 5 despite the presence of the unprotected C7 hydroxyl. [17,26] The formation of Fragment D is accomplished via asymmetric iridium-catalyzed alcohol-mediated carbonyl anti-crotylation [16] of the allylic alcohol 10, which is prepared via zirconium-catalyzed carboalumination of propargyl alcohol Scheme 1.…”