Hindered organoboron groups in organic chemistry. Part 22. Some interesting properties of 2,4,6-triisopropylphenylborane (tripylborane, TripBH2), a new useful monoarylborane
2,4,6-Triisopropylphenylborane (tripylborane, TripBH2) is a solid, stable, hydroborating agent that hydroborates monosubstituted alkenes to give either TripBHR1 or TripBR21. TripBHR1 can be converted into mixed boranes TripBR1R2(R1, R2= primary alkyl, Rp) and TripBRpRs and TripBR2s are also readily available. Oxidation of these products gives the corresponding alcohols in excellent yields, with a high selectivity for alkan-1-ols in the cases of groups derived from alk-1-enes. Cyanidation of TripBR2 proceeds to give ketones without migration of the aryl group. This establishes the low migratory aptitude of the aryl group and also that no scrambling of alkyl groups occurs. The tripyl group of TripBR2p can be selectively removed.