Crystal structure of a 1,1-dibutyl-1H,3H-naphtho[1,8-cd][1,2,6]oxastannaborinin-3-ol.

Kevin Breitwieser,Peter Chen

doi:10.1107/s2056989021000712

Abstract

The title oxastannaborininol compound, [Sn(C4H9)2(C10H7BO2)], has been synthesized and crystallized. While heterocycles containing a C-O-B group are common, heterocycles containing an E-O-B unit, where E is an element of the carbon group except for carbon, are rare. In fact, while heterocycles containing Si-O-B units are occasionally reported (although without crystal structures), there are no reports for the corresponding germanium, tin or lead analogues. Herein, the first synthesis and crystal structure of a heterocycle containing an Sn-O-B unit is described. The asymmetric unit contains one mol-ecule showing a notable disorder of the tin atom and the butyl groups. They occupy two sets of positions with site-occupancy factors of 0.295 (6) and 0.705 (6).

Highlights

The title oxastannaborininol compound, [Sn(C4H9)2(C10H7BO2)], has been synthesized and crystallized
While heterocycles containing a C–O–B group are common, heterocycles containing an E–O–B unit, where E is an element of the carbon group except for carbon, are rare
While heterocycles containing Si–O–B units are occasionally reported, there are no reports for the corresponding germanium, tin or lead analogues

Summary

Chemical context

Both tin and boron organic compounds are widespread reagents for cross-coupling reactions in organic synthesis (Negishi, 2002). The combination of tin- and boron-containing groups in one molecule can be advantageous, as they can undergo cross-coupling under different conditions. While the stannyl group undergoes transmetalation at elevated temperatures, a boronic acid will not do so with an additional activator, usually a base (Cardenas, 2003). Su and Hartwig on the other hand synthesized oxasiliaboroninol 4 using ruthenium catalysis (Su et al, 2018) In their report, they describe multiple transformations for this product, being able to replace selectively the boronic acid group while leaving a silanol group behind. It shows notable disorder of the tin atom and the butyl groups. They occupy two sets of positions with site-occupancy factors of 0.295 (6) and 0.705 (6). The B—C bond has a length of 1.594 (3) A , the B—O bond lengths are 1.352 (3) A (B—OSn) and 1.362 (3) A (B—OH)

Database survey

Synthesis and crystallization

Refinement