Preparation of Alcohols from Alkenes via the Homologation of Boronates with (Trimethylsilyl)diazomethane

Abstract

Alkylcatecholboranes obtained from alkenes were converted to the corresponding alkylmethanols by reaction with (trimethylsilyl)diazomethane followed by oxidation and treatment with fluoride.

Unveiling the role of boroxines in metal-free carbon–carbon homologations using diazo compounds and boronic acids

“…Organoboranes are known to react fast with TMSCHN 2 ( 2 ) at –78 °C while catecholboranes need heating (60 °C) over an extended time period (12 h). 27 , 45 Both the reported reactivities as well as the experimentally observed behaviour of boroxines are in good correlation with our calculations. To prove that both the MIDA 7 and pinacol boranes 8 are not reactive, the substrates were treated with TMSCHN 2 ( 2 ) at reflux in toluene for 3 d. In all cases, no homologation products were observed.…”

“… 16 , 24 – 26 Additionally, the homologation using TMS-diazomethane (TMSCHN 2 ) and organoboron compounds is useful to install a trimethylsilyl and boron functionality in a metal-free fashion. 27 – 32 These doubly functionalised carbon substrates are of interest, as they may be used to generate sequential or orthogonal functionalization at the same carbon atom. 28 , 29 To date, the homologation with TMSCHN 2 has only been performed in combination with boronic acids to access the TMS-free homologation products.…”

Transition‐Metal‐Free C(sp2)–C(sp2) Cross‐Coupling of Diazo Quinones with Catechol Boronic Esters

“…We propose that the B–O interaction might facilitate the generation of the quinone carbene. This is because generating a carbene through the direct thermolysis of a diazo quinone commonly requires a high temperature (above 70 °C), and the reaction of donor‐type TMS diazomethane (TMSCHN 2 ) with 2 g‐1 would require heating (60 °C) over an extended time period (15 h), unlike the milder reaction conditions reported in this work. The addition of 3 equiv of 1 a significantly inhibited the reaction, leading to a low product yield (14 %) and increased generation of the phenol byproduct (13 %) (Scheme a).…”

Catalytic Asymmetric Hydroboration: Recent Advances and Applications in Carbon−Carbon Bond‐Forming Reactions

“…[117] After homologation with this reagent, the BϪC bond is oxi- Table 8. [117] After homologation with this reagent, the BϪC bond is oxi- Table 8.…”

“…Le Gall and Mioskowski have also reported that TMSCHN 2 can be used to homologate boronate esters. [117] After homologation with this reagent, the BϪC bond is oxi- Table 8. Homologation of boronate esters with halomethane reagents dized to give a vicinal silyl alcohol, and the SiϪC bond cleaved with TBAF.…”