Functionalisation of zirconacyclopentanes and zirconacyclopentenes

Some of the methods available for elaborating zirconacycles are outlined below. 

Treatment of zirconacyclopentanes with bromine, iodine, or A-bromosuccin-imide (NBS) gives the 1,4-dihalide in good yield. Selective monohalogenation 

Reaction of a variety of zirconacyclopentadienes, -enes, and -anes with main group element dihalides (or E2CI2 for E = S, Se) gives the corresponding elementacycles 5 -61.  

E = BPh, PPh, AsPh, SbCI. BiCI, GaCI, InCI GeCl2, SnMe2, SiBr. 

The following protocols describe the synthesis of zirconacycle 45 from 1,6-heptadiene and its characterisation by NMR spectroscopy. Zirconacycle 45 is then elaborated into alcohol 49 by reaction with carbon monoxide, and alcohol 54 (R = Ph) by tandem insertion of lithium chloroallylide and benzaldehyde. 

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