Recently we have shown that retro-Nazarov reactions are under the control of geminal bond participation. In retro-Nazarov reactions, electrocyclic ring-opening must occur in a conrotatory manner, so that a geminally 4,4-disubstituted substrate and cis-4,5-disubstituted substrate may exhibit the same torquoselectivity with a substituent effect. For amino-hydroxy substituted substrates, however, cis-5-amino-4-hydroxy substituted 9 was calculated preferentially to give E-amino-Z-hydroxy product Z-12, while geminally disubstituted 4-amino-4-hydroxy 11 was expected to predominantly afford Z-amino-E-hydroxy product E-12. We demonstrate here that this discrepancy in torquoselectivity can be explained in terms of geminal bond participation: in 9, the most electron-donating sigma-bond is sigma(CH) geminal to the amino group, which should rotate inwardly. Thus, the amino group should rotate outward. On the other hand, the sigma(CN) bond is more electron-donating than the sigma(CO) bond, which results in inward rotation of the amino group in 11. (C) 2015 Elsevier Ltd. All rights reserved.