Tetra-tert-butylethylene, fantasy, fake, or reality?

Abstract

This paper reviews all recent attempts to prepare tetra-tert-butylethylene. Some of the synthetic pathways approached this molecule very close but failed during the last step. According to recent DFT calculations this alkene should be a stable molecule with a strain energy in the range of 93 kcal/mol. Since all synthetic approaches failed new methodologies have to be developed, that is either synthesis of the perfluoro derivative of this alkene or the reaction of the radical cation or the radical anion of di-tert-butylmethane with the carbene by a crossed beam technique in the gas phase.(2) Di-tert-butyldiisopropylpropylethylene (3) Tri-tert-butylethylethylene (4) Tetraaldehyde (5) Di-tert-butylcarbene (6) anti-fenchylidenefenchane (7) 1,2-Di-tert-butyl-3,3,5,5-tetramethylcyclopentene (8) Tetra-tert-butylethane (9) 1,1-Dimethyl-2-tert-butylcyclopropane

Are Allenes with Zwitterionic Character Still Allenes? Of Course!

“…The answer appears to be yes. Are not highly twisted3 or pyramidalized4 alkenes still alkenes, and small‐ring alkynes5 still alkynes, despite their unusual geometries and reactivities? Consider the class of push–pull substituted alkenes, such as 2 a…”

Are Allenes with Zwitterionic Character Still Allenes? Of Course!

“…The answer appears to be yes. Are not highly twisted [3] or pyramidalized [4] alkenes still alkenes, and small-ring alkynes [5] still alkynes, despite their unusual geometries and reactivities? Consider the class of push-pull substituted alkenes, such as 2 a.…”

Synthesis of some fenchyl-substituted alkenes and enol-ethers containing 3-oxyphenyl substituents by the Barton-Kellogg reaction

“…34 This approach allowed us to calculate 1 H and 13 C chemical shifts of 1a and 1b, which were compared to the experimental data ( Figure S8). 35 The adjusted coefficients of determination (adj-R 2 …”