Synthesis and Structure of an Azatrisilacyclobutane and Its Precursor, a Novel Lithium Enamide Having a Tricyclic (LiNSiO)2 Skeleton

✍ Scribed by Floria Antolini; Barbara Gehrhus; Peter B. Hitchcock; Michael F. Lappert

• Book ID: 101374813
• Publisher: John Wiley and Sons
• Year: 2002
• Tongue: English
• Weight: 192 KB
• Volume: 41
• Category: Article
• ISSN: 0044-8249
• DOI: 10.1002/1521-3773(20020715)41:14<2568::aid-anie2568>3.0.co;2-z

✦ Synopsis

We report results that have a bearing on two diverse but related and currently topical areas of organometallic chemistry. The first concerns insertion of an a-hydrogen-free nitrile into an LiÀC bond, and specifically of 1-adamantyl cyanide (AdCN) into the chiral bis(silyl)methyl compound Li-[CH(SiMe 2 OMe)(SiMe 3 )] [1] to yield the lithium enamide 1. The second deals with the insertion of the thermally stable bis(amino)silylene Si[(NCH 2 tBu) 2 C 6 H 4 -1,2] (Si(NN)) 2 [2] into an LiÀN bond, and particularly of Si(NN) into 1 to afford the azatrisilacyclobutane 3, in which a transient insertion product 4 is a plausible intermediate.

The reactions and conditions leading to the new colorless crystalline compounds 1 and 3 are summarized in Scheme 1.

Scheme 1. Synthesis of 3 via 1.

The yields (1, 64%; 3, 50 %) of X-ray quality crystalline materials were not optimized. Each of 1 and 3 revealed the parent molecular ion in the EI mass spectra and gave satisfactory microanalyses and multinuclear NMR spectra.

The crystalline lithium enamide 1 is a centrosymmetric dimer (Figure 1). [3] It has a rhomboidal, planar (LiN) 2 core (the endocyclic angles at the Li atoms are wider than those at the N

[5] M.