Beilstein J. Org. Chem.2018,14, 2354–2365, doi:10.3762/bjoc.14.211
; crystal structures; homeomorphicisomerization; hydrogenation; in/out isomers; metathesis; phosphine boranes; Introduction
We have found that a variety of metal complexes with trans-phosphine ligands of the formula P((CH2)mCH=CH2)3 (1; m = 4–14) undergo threefold interligand ring closing alkene
2 and 3: in,in, out,out, and in,out (identical to out,in). The first two, as well as the degenerate in,out pair, can rapidly interconvert by a process termed homeomorphicisomerization [26][27], which is akin to turning the molecules inside out. Readers are referred to earlier publications in this
triarylphosphorus bridgeheads and p-phenylene containing tethers that are long enough to allow rapid homeomorphicisomerization. The precursor 18·2(=O) was prepared by a threefold Williamson ether synthesis in surprisingly high yields (61% in,in/out,out and in,out combined) [50][51], likely aided by the geminal
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Graphical Abstract
Scheme 1:
Syntheses of gyroscope like platinum and rhodium complexes and dibridgehead diphosphines derived th...