Depending on the variation of the temperature and on the nature of the substituent of alk-1-ynes 2, the enantioselectivity of the deltacyclene formation in the cobalt catalysed [2 + 2 + 2] cycloaddition of norbornadiene 1 and acetylenes 2, can be achieved with up to 98%. The best enantioselectivities observed around WC are in agreement with the Isoinversion principle (lip). (C) 2002 Elsevier Science B.V. All rights reserved.