Towards 2-silaallenes: Synthesis of spirocyclic precursors

Article abstract of DOI:10.1002/chem.19970030617

Reactions of dichlorodivinylsilane(2) and Li/Bu in a molar ratio 1/1 and 12 lead to highly reactive intermediates, which can be trapped by suitable reagents. In the presence of trimethylmethoxysilane, norbornadiene, anthracene and dipheylacetylene, products are formed that provide evidence for the intermediate formation of both the neopentylsilene H₂C=CH(Cl)Si=CHCH₂tBu (3) and the 2-silaallene tBuCH₂CH=Si=CHCH₂tBu(4). The formation of double cycloadducts from 4 is particularly interesting as a preparatively facile route for the synthesis of silaspirocycles such as 13, 16 and 17, which have been characterized by single-crystal X-ray structure analysis.