title: Computational and experimental structure-reactivity relationships: evidence for a side reaction in Alpine-Borane reductions ofd-benzaldehydes.
abstract: Extraordinary stereoselectivity, approaching 100%, has been reported in the reductions ofd-benzaldehydes byB-isopinocampheyl-9-borabicyclo[3.3.1]nonane (Alpine-Borane). This is likely because of the extreme size disparity of groups on either side of the carbonyl. Here, we present a structure-reactivity study whereby the reductions of variably substitutedd-benzaldehydes are explored using highly sensitive measures for enantiomeric excess and relative reactivity. These results are compared to the relative rates predicted from density functional calculations. The results indicate that 2,6-disubstitution adversely affects the stereoselectivity by means of a non-selective reduction via the dehydroboration product of Alpine-Borane, 9-borabicyclo[3.3.1]nonane.
authors.affiliation: School of Natural Sciences, University of California, Merced, PO 2039, Merced, CA 95344, USA.
authors.forename: Hui
authors.initials: H
authors.lastname: Zhu
authors.affiliation: School of Natural Sciences, University of California, Merced, PO 2039, Merced, CA 95344, USA.
authors.forename: N Soledad
authors.initials: NS
authors.lastname: Reyes
authors.affiliation: School of Natural Sciences, University of California, Merced, PO 2039, Merced, CA 95344, USA.
authors.forename: Matthew P
authors.initials: MP
authors.lastname: Meyer