English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Tools annual

Global: Zendy Free Plan

Global: Zendy Tools monthly

Global: Zendy Plus monthly

In the course of 1,1-carboborations, the activation of polar Si-C and Sn-C bonds by electrophilic triorganoboranes, BR3 (R = alkyl. aryl, C6F5) is used to build new C-C bonds. Expectedly, alkynyltin compounds were found to be much more reactive than the corresponding silanes. Monoalkynyl derivatives lead to organometallic-substituted alkenes, quantitatively and stereoselectively in most cases. Dialkynylsilanes R 2 2Si(CC-R 1 )2 (R 1 = alkyl, aryl, silyl; R 2 = H, alkyl, allyl, vinyl, aryl, Cl) react with BR3 via twofold 1,1-carboboration by selective formation of siloles. In the case of dialkynylstannanes R 2 2Sn(CC-R 1 )2, (R 1 = alkyl, aryl, silyl; R 2 = alkyl, benzyl, aryl, amino) the analogous reactions lead mainly to stannoles or alternatively to 1-stanna4-bora-cyclohexa-2,5-diene derivatives, depending in a complex way on substitutents R at boron and R 1 at the CC bond. The high reactivity of the Sn-C bonds allows the reactions to be conducted under mild conditions enabling the isolation and structural characterisation of intermediates. These possess a zwitterionic structure, in which typically an almost trigonal planar surrounded tin atom is side-on coordinated to the CC bond of an alknylborate unit. Extending these reaction principles to tetraalkynylsilanes Si(CC-R1)4, one obtains 1,1'-spirobisiloles via fourfold 1,1organoboration. Similarly, 1,1'-spirobistannoles can be prepared starting from some tetraalkynylstannanes Sn(CC-R1)4 (R 1 = i Pr, t Bu, SiMe3).

Activation of Silicon- and Tin-Carbon Bonds. 1,1-Carboboration of Alkynylsilanes and -stannanes