Torquoselective
Ring Opening of Fused Cyclobutenamides:
Evidence for a <i>Cis,Trans</i>-Cyclooctadienone Intermediate
Xiao-Na Wang
Elizabeth H. Krenske
Ryne C. Johnston
K. N. Houk
Richard P. Hsung
10.1021/ja502252t.s001
https://acs.figshare.com/articles/journal_contribution/Torquoselective_Ring_Opening_of_Fused_Cyclobutenamides_Evidence_for_a_i_Cis_Trans_i_Cyclooctadienone_Intermediate/2039211
Electrocyclic
ring opening of 4,6-fused cyclobutenamides <b>1</b> under thermal
conditions leads to <i>cis,trans</i>-cyclooctadienones <b>2</b>-<i>E</i>,<i>E</i> as transient intermediates,
en route to 5,5-bicyclic products <b>3</b>. Theoretical calculations
predict that 4,5-fused cyclobutenamides
should likewise undergo thermal ring opening, giving <i>cis,trans</i>-cycloheptadienones, but in this case conversion to 5,4-bicyclic
products is thermodynamically disfavored, and these cyclobutenamides
instead rearrange to vinyl cyclopentenones.
2015-12-17 04:12:40
ci
bicyclic
cyclobutenamides 1
Fused Cyclobutenamides
case conversion
Torquoselective Ring
ring opening
vinyl cyclopentenones