Synthesis and properties of 2,4,6-trimethylphenylborane (mesitylborane), a stable alternative to thexylborane

Four advantageous properties characterize mesitylborane MesBH2 as a reagent: (1) It is readily accessible and quite stable. (2) It can be treated with two different 1-alkenes in a stepwise fashion (→ MesBR1R2). (3) The regioselectivity of each individual step is > 99%. (4) The products MesBR1R2 can be readily transformed via MeOBR1R2 or directly to BR1R2R3. MesBR2 and BR1R2R3 are important precursors for the synthesis of ketones R1R2CO and tertiary alcohols R1R2R3COH, respectively, by the cyanoborate process