Neutral cyclic sp²–sp³ and sp³–sp³ diboranes from N,N′-dicyclohexylcarbodiimide insertion into 1,2-dichlorodiboranes(4)

Abstract

New derivatives of sp2–sp3 and sp3–sp3 diboranes were prepared via a carbodiimide-induced rearrangement process.

Neutral and Anionic Diboron Compounds Bearing Electron‐Precise B−B Bond

“…A class of sp 2 ‐sp 3 diboron compounds ( 40 – 46 ) has been developed in the past few years (Figure 3). [43–46] In general, these sp 2 ‐s‐p 3 diboron compounds can be prepared through the Lewis acid‐base reaction of diboron(4) compounds with Lewis bases. Compared with tetraaryl‐substituted sp 2 –sp 2 diboron compounds (such as compound 7 ), the Lewis acidity of the boron centers in these sp 2 –sp 3 diboron compounds is reduced.…”

“…A class of sp 2 -sp 3 diboron compounds (40)(41)(42)(43)(44)(45)(46) has been developed in the past few years (Figure 3). [43][44][45][46] In general,…”

The Catalyst’s Companion: N,N′-Dicyclohexylcarbodiimide (DCC) in Action

“…When one equivalent of DCC ( 7) is reacted with B 2 Cl 2 R 2 15 (R = dimethylamine, Dur) in toluene at room temperature, the resultant carbodiimide-induced rearrangement products are monocyclic sp 2 -sp 3 diboranes 16. 13 (E) To explore the usage of DCC as an activating agent, Vanhaecht et al synthesized aliphatic polyester. It is thought that a carboxylic acid and a DCC molecule generate an O-acylisourea intermediate 19 as part of the mechanism of carbodiimide condensation.…”

“…It is thought that a carboxylic acid and a DCC molecule generate an O-acylisourea intermediate 19 as part of the mechanism of carbodiimide condensation. 13 From this intermediate, several reactions are possible. The intramolecular migration of an acyl group from an oxygen atom to a nitrogen atom results in the formation of N-acyl urea 17 (route A).…”