%0 Journal Article
%A Selzer, Tzvia
%A Rappoport, Zvi
%D 1996
%T Bis(dimesitylmethylene)-1,3-dithietane, -1,2,4-trithiane, and
-1,2,4,5-tetrathiane. Conformation and DNMR Study. Observable
Dimesityl Thioketene
%U https://acs.figshare.com/articles/journal_contribution/Bis_dimesitylmethylene_-1_3-dithietane_-1_2_4-trithiane_and_-1_2_4_5-tetrathiane_Conformation_and_DNMR_Study_Observable_Dimesityl_Thioketene/3703158
%R 10.1021/jo960911k.s001
%2 https://ndownloader.figshare.com/files/5793600
%K P 2 S 5
%K Observable Dimesityl Thioketene
%K kcal mol
%K dimesityl thioketene 2
%K tetrathiane ring
%K signal
%K dimesityl ketene
%K propeller conformation
%K analog
%K bi
%K Static NMR data
%K dimesitylmethylene moieties
%K Ditipylketene forms
%K DNMR Study
%K enantiomer
%K meso form
%K 160 K
%K threshold barriers
%K Diphenylacetyl chloride
%X The reaction of dimesityl ketene with P2S5
and pyridine gives 2,4-bis(dimesitylmethylene)-1,3-dithietane (3),
3,6-bis(dimesitylmethylene)-1,2,4,5-tetrathiane (4),
3,5-bis(dimesitylmethylene)-1,2,4-trithiane (5), and dimesityl thioketene 2 as a
transient. The structures of 3 and 4 were
determined
by X-ray crystallography. The dimesitylmethylene moieties in
3 and 4 have a propeller conformation, and the tetrathiane ring in 4 has a twist-boat
conformation. Static NMR data are consistent
with the presence of two enantiomers and one meso form for 3
and of three pairs of enantiomers
for 4. The several aromatic signals observed for
3 and 4 at slow exchange at 160 K coalesce to
a
single signal at higher temperatures. The threshold barriers for
these dynamic processes are 12.7
(3) and 13.3 (4) kcal
mol-1, and the dynamic behavior was analyzed
in terms of flip processes. On
standing, a solution of 3 develops a blue color which is
attributed to formation of 2, by
retro-dimerization of 3. Diphenylacetyl chloride gives
with P2S5 the analog of 5 and its
one-double
bond reduction product. Ditipylketene forms a product identified
tentatively as the analog of 3.
%I ACS Publications