e.g. Filippa Pettersson or Cancer Res. 75(6) , 1102-12, (2015) or 10.1002/anie.201600521
trans Deformation of a carbon–carbon triple bond in response to incipient nucleophilic attack: the X-ray crystal structure of ethyl 3-(2-nitrophenyl) propynoate at 150 K
CR Rice, JD Wallis
Index: Rice, Craig R.; Wallis, John D. Journal of the Chemical Society, Chemical Communications, 1993 , # 6 p. 572 - 574
In the title compound 1 the electron-deficient alkyne bond shows a pronounced trans distortion in response to an adjacent electron rich nitro O atom, suggesting that the more favourable reaction coordinate for addition of nucleophiles to activated alkynes involves trans rather than cis addition.