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The Molecular Structure of 3‐ tert ‐Butyl‐4,4‐dimethyl‐2‐pentenal (3,3‐Di‐ tert ‐butylpropenal)
Author(s) -
Hopf Henning,
Mlynek Cornelia,
Klein Dagmar,
Traetteberg Marit,
Bakken Pirkko
Publication year - 2001
Publication title -
european journal of organic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.825
H-Index - 155
eISSN - 1099-0690
pISSN - 1434-193X
DOI - 10.1002/1099-0690(200104)2001:7<1385::aid-ejoc1385>3.0.co;2-p
Subject(s) - chemistry , steric effects , conjugated system , ab initio , aldehyde , double bond , stereochemistry , bond length , crystallography , computational chemistry , crystal structure , organic chemistry , polymer , catalysis
The highly strained conjugated aldehyde 3‐ tert ‐butyl‐4,4‐dimethyl‐2‐pentenal (3,3‐di‐ tert ‐butylpropenal; abbreviated D33; 4 ) has been prepared, and its molecular structure and conformation have been studied experimentally by the gas electron diffraction method and by theoretical ab initio (HF/6‐31G*) calculations. The propenal skeleton assumes an anti conformation, and the steric strain is primarily manifested in the following structural details: The C=C−C angle is substantially larger than normal [GED: 132.6(7)°; HF/6‐31G*: 132.5°]; the ( Z )‐oriented tert ‐butyl group is twisted to a nearly staggered position relative to the C=C double bond, forming a cogwheel system with the other tert ‐butyl group, which has the normal eclipsed conformation relative to C=C; the C 3 −C t Bu (formally sp 2 −sp 3 ) bonds are elongated compared to those in unstrained compounds, and are longer than the (formally sp 3 −sp 3 ) C−CH 3 bonds.