Coupling constants isonitriles

A minor isonitrile named acanthellin-2 with a specific rotation of — 24.1° was reported with no further details except some IR and MS data [3]. Isothiocyanate 15 and formamide 16 were also isolated from Axinella cannabina in a later study, in which isonitrile 14 and isomers 17-19 were also secured [35]. That 17-19 are C4(14)-ene isomers of 14 was concluded after extensive double resonance H NMR experiments. Coupling constants and nOe effects between the affected protons and various substituents of 17 established the relative stereochemistry of this series. 

Holloway (14) has determined chemical shifts and the Jn-c coupling constant for the boron isonitrile complex (CH3)3CNCB(CHs)3 = C = 157.8... 

Table 7.28. J Coupling constants of nitriles, isonitriles and protonated...

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