Note: $H_3O^+$ looks like $H_3O^-$ due to thin width of vertical bar in $+$
During HBO, the carbon nearer to the phenyl ring is more sterically hindered than the other one next to it, otherwise these two are similar in many respects exscluding some, this can be understood by imagining the intermediate $R_3B$ by taking R as branched through both carbons one by one, maybe then you'll appreciate the fact of difference in steric hindrance.
In case of acid catalyzed hydration, the carbon nearer to it has more carbocation stabilization than the one next to it, because of the conjugation with the benzene/phenyl ring. Even if the carbocation is formed on the $\beta$ wrt phenyl, it'll rearrange to $\alpha$/allylic position.Thus the product.
Herbert C. Brown (1912–) won the Nobel Prize in 1979 for his invention and development of hydroboration, mostly carried out at Purdue University, which made this new chemistry familiar to the practising organic chemist. The prize was shared with Georg Wittig, showing how important organic chemistry with main group elements had become. He vigorously opposed ‘non-classical’ carbocation theory.
For most substrates, the addition in hydroboration is stereospecific and syn,
with attack taking place from the less-hindered side.
Brown, H.C.; Zweifel, G. J. Am. Chem. Soc. 1961, 83, 2544; Bergbreiter, D.E.; Rainville, D.P.
J. Org. Chem. 1976, 41, 3031; Kabalka, G.W.; Newton, Jr., R.J.; Jacobus, J. J. Org. Chem. 1978,
The only special case known (atleast to me) is the treatment of iPrCHCHMe with borane which
gave 57% of product with boron on the methyl-bearing carbon and 43% of the
otherBrown, H.C.; Zweifel, G. J. Am. Chem. Soc. 1961, 83, 1241.
In all cases, the boron goes to the side of the double bond that has more hydrogens,
whether the substituents are aryl or alkylFor a thorough discussion of the regioselectivity with various types of substrate and hydroborating
agents, see Cragg, G.M.L.Organoboranes in Organic Synthesis Marcel Dekker, NY, 1973, pp.63–84,
137–197. See also, Brown, H.C.; Vara Prasad, J.V.N.; Zee, S. J. Org. Chem. 1986, 51, 439.