Easy Access to Phosphine-Borane Building Blocks.

Authors :: de Jong GB
Ortega N
Lutz M
Lammertsma K
Slootweg JC
Source :: Chemistry (Weinheim an der Bergstrasse, Germany) [Chemistry] 2020 Dec 04; Vol. 26 (68), pp. 15944-15952. Date of Electronic Publication: 2020 Oct 23.
Publication Year :: 2020
Abstract: In this paper, we highlight the synthesis of a variety of primary phosphine-boranes (RPH <subscript>2</subscript> ⋅BH <subscript>3</subscript> ) from the corresponding dichlorophosphines, simply by using Li[BH <subscript>4</subscript> ] as reductant and provider of the BH <subscript>3</subscript> protecting group. The method offers facile access not only to alkyl- and arylphosphine-boranes, but also to aminophosphine-boranes (R <subscript>2</subscript> NPH <subscript>2</subscript> ⋅BH <subscript>3</subscript> ) that are convenient building blocks but without the protecting BH <subscript>3</subscript> moiety thermally labile and notoriously difficult to handle. The borane-protected primary phosphines can be doubly deprotonated using n-butyllithium to provide soluble phosphanediides Li <subscript>2</subscript> [RP⋅BH <subscript>3</subscript> ] of which the phenyl-derivative Li <subscript>2</subscript> [PhP⋅BH <subscript>3</subscript> ] was structurally characterized in the solid state.<br /> (© 2020 The Authors. Published by Wiley-VCH GmbH.)