Vinyloxyborane and its isomers. An ab initio study of the C2H5BO potential energy surface, the barrier to 1,3-shifts in β-ketoboranes, and the mechanism of the carbonylation reaction of boranes

✍ Scribed by Mustafa R. Ibrahim; Michael Bühl; Reinhard Knab; Paul Von Rague Schleyer

• Publisher: John Wiley and Sons
• Year: 1992
• Tongue: English
• Weight: 433 KB
• Volume: 13
• Category: Article
• ISSN: 0192-8651
• DOI: 10.1002/jcc.540130405

✦ Synopsis

Vinyloxyboranes, CH2=CH-O-BR2, are shown by ab initio molecular orbital theory to be more stable than the isomeric p-aldoboranes, R2B-CH2-CH=O, by ca. 19 kcal/mol. The MP2/6-31G*/6-31G* + ZPE barrier for the [1,3] boron shift is only 10.9 kcal/mol (R = Me) relative to the aldoborane. Other C,H,BO isomers (aketoboranes, boraepoxides and organoboron oxides), which are related to the proposed stages in the carbonylation reaction of boranes, are shown to be plausible intermediates. However, some of the computed barriers for methyl group migrations are unrealistically large, up to ca. 63 kcal/mol.