While twofold extrusion procedures have proved to be very useful in the preparation of very sterically hindered olefins, the extremely hindered tetra-tert-butylethylene (1) has remained elusive. An approach to 1 based on" tied-back''intermediates such as the selone 13 and diazo compound 14 was investigated. Although 1, l-di-phenyl-2, 2-di-tert-butylethylene (16) could be prepared by a combination of twofold extrusion and reductive cleavage, no ...
