Last but not least, the substituent M is placedantito the aldehyde group, allowing minimization of steric effects of the
â-stereocenter and the carbonyl group by
aligning the smallest substituent H with the carbonyl
oxygen. Consequently, the 1,3-anti-diol would be
predicted again as the major product, which is indeed
obtained in many cases with high selectivity (Scheme
80, Table 41).