Structural studies of organoboron compounds LXII. Synthesis and structure of various N-alkylated 1,3-dioxa-4-aza-2-boracyclohexanes

Abstract

The synthesis of a number of variously substituted N-alkyl 2-hydroxyaminoalkanols 3 and their reactions with phenylboronic acid are detailed. The crystalline products proved to be 1:2 condensates 4 in a few cases and 1:1 condensates 5 in all the other cases studied. Crystals of 2-mesityl-6,6-pentamethylene-1,3-dioxa-4-aza-2-boracyclohexane, 5l, are triclinic, a = 11.540(2), b = 10.402(3), c = 8.440(2) Å, α = 108.86(2)°, β = 97.62(2)°, γ = 89.36(2)°, Z = 2, space group [Formula: see text] and those of 4,4′-methylenebis(6,6-pentamethylene-2-phenyl-1,3-dioxa-4-aza-2-boracyclohexane) benzene solvate, 15a•C6H6, are monoclinic, a = 22.690(1), b = 16.867(1), c = 8.4783(9) Å, β = 104.912(8)°, Z = 4, space group C2/c. The structures were solved by direct methods and refined by full-matrix least-squares procedures to R = 0.037 and 0.035 (Rw = 0.035 and 0.044) for 3190 and 2084 reflections with I ≥ 3σ(F2)• respectively.