Boraformylation and Silaformylation of Allenes

Abstract

The boraformylation of allenes with B (pin) and a formate ester as boron and formyl source, respectively, proceeds in the presence of a copper catalyst. The reaction selectively affords the corresponding β-boryl β,γ-unsaturated aldehydes in good to high yields. Furthermore, the silaformylation of allenes was achieved with a formate ester and PhMe Si-B(pin) as the silicon source.

Alkenyl Boronates: Synthesis and Applications

“…Hoveyda et al described the asymmetric protoboration of these substrates catalyzed by chiral NHCcopper complexes. [66] With the appropriate choice of reagents, boraformylation, [67] boroacylation, [68,69] boraalkoxyoxalylation, [69] or asymmetric diboration [70] have been reported with different copper(I)-phosphine catalytic systems.…”

A Copper(I)‐Catalyzed Enantioselective γ‐Boryl Substitution of Trifluoromethyl‐Substituted Alkenes: Synthesis of Enantioenriched γ,γ‐gem‐Difluoroallylboronates

“…[8] Asymmetric copper-catalyzed borylations represent ap owerful tool for the synthesis of optically active organoboron compounds. [9] We and other groups have reported the asymmetric synthesis of allylboron compounds via the asymmetric boryl substitution of allylic compounds (Scheme 1a). [10] Thea llylboration of aldehydes with enantioenriched allylboronates generally proceeds in ah ighly stereospecific manner.…”

Transition-metal Catalyzed Synthesis of Carbonyl Compounds Using Formates or Formamides as Carbonyl Sources

“…We found that boraformylation of allenes could be achieved by employing B2(pin)2 and a formate ester as the boron and formyl sources, respectively, in the presence of a copper catalyst 26) . Reaction of 3-methyl-1,2-nonadiene (11a), B2(pin)2, and hexyl formate (1g) was carried out at 50 by employing 3.0 mol% of CuOAc and 4.0 mol% of a ligand in toluene (Scheme 13).…”