Spirotin compounds

Tetraalkyl-l,6-dihalogeno-2,3,4,5-tetracarba-nido-hexaboranes(6) 56d were obtained in high yield by another route (Scheme 3.2-30), taking advantage of the exchange reactions of the spirotin compounds 57 with boron halides. 

Scheme 3.2-30. Classical spirotin compounds 57 react with boron trihalides to give the 1,6-dihalogeno-substituted nido-C4B2 clusters 56d (X = Cl, Br, I R = Et, Bu).

Structure of a novel spirotin compound. Wrackmeyer and co-workers reported an interesting multinuclear NMR study in which they demonstrated that 2,3-dichloro-l,3-bis-(trimethylsilyl)-l,3,2-diazastanna-[3]ferrocenophane reacts with lithium alkynides to give the corresponding di(alkyn-l-yl)tin derivatives, 246, that on subsequent organo-boration with triethylborane affords a novel spirotin compound that contains both ferrocenophane and a stannacyclopentadiene ring. 

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