Structural studies of organoboron compounds LI. N-Methylhydroxylamine(O-B)2,5-diphenyl-1,3,2-dioxaborolan-4-one

Abstract

[Traduit par la redaction]

Structural studies of organoboron compounds LXIV. Boron chelate formation with glycolohydroxamic acids, and the crystal and molecular structure of 5-(1-hydroxycyclohexyl)-2,2-diphenyl-1,3-dioxa-4-azonia-2-borata-4-cyclopentane

“…Structure 4 would involve the alkanol and the carbonyl groups as chelating ligands, as found in the five-membered difluoroboron chelate moiety of compound 7, the molecular structure of which has been determined by an X-ray crystallographic analysis (14). The fivemembered isomer 5, which would have to be formed by a very weak N+B donor bond from the amide nitrogen atom to the boron atom, seems quite improbable.…”

“…In the course of our investigations of hydroxamic acids as bi-or polydentate ligands in the formation of boron chelates (2)(3)(4)(5)(6)(7)(8)(9)(10)(11)(12)(13)(14)(15) ' Previous paper in this series: ref. 24.…”

Structural studies of organoboron compounds. LII. N-Ethylhydroxylamine- (O-B)1,7-diethyl-3,5-diphenyl-2,4,6-trioxa-7-aza-1-azonia-3-bora-5- boratabicyclo[3.3.0]octane

“…The ele-'~revious paper in this series: ref. 11. 23-(1-Oxa-2-azoniabutyl) -1,7-diethyl-3,s -diphenyl-2,4,6-trioxa-7-aza-1-azonia-3,s-diboratabicyclo[3.…”

Structural studies of organoboron compounds. LX. Reaction of sterically hindered arylboronic acids with 2-(hydroxyamino)alkanols. Crystal and molecular structure of 2-mesityl-6,6-pentamethylene-1,3-dioxa-4-aza-2-boracyclohexane

“…This arrangement was noted for the related spiro compounds 9 (9). The most obvious differences between the bond lengths of the N-unsubstituted and the N-acylated BONCCO rings of 3c and 9, respectively, are those involving the nitrogen atoms.…”

“…The N-0 distance in 3c (mean 1.465 A) is djstinctly longer than those in 9a (1.401(1) A) and 9b (1. 402(3) A). The intra-annular C-N bonds in 3c (mean 1.353 A) appear to be considerably shorter than the corresponding bonds in 9a (1.448(2) A) and 9b (1.440(4) A) (9), but in this case imperfect modeling of the disorder (see Experimental) may be partially responsible even though some shortening is expected. The distances between the resolved, disordered, N and 0 atoms are almost certainly more realistic.…”