TY - JOUR
T1 - Cyclic Acetals. Structural Analysis of 1,3‐Dioxepine and Related Compounds
AU - Jørgensen, Flemming S.
AU - Gajhede, Michael
AU - Frei, Bruno
PY - 1985/1/1
Y1 - 1985/1/1
N2 - The He(I) PE spectra of 1,3‐dioxepine (1) and the related bicyclic acetals 1,3,7,7‐tetramethyl‐2,11‐dioxabicyclo[4.41]undeca‐3,5‐dien‐10‐one (2) and 1,3,7,7‐tetramethyl‐10‐methylidene‐2,11‐dioxabicyclo[4.4.1]undeca‐3,5‐diene (3) have been recorded and analyzed. Interpretation of the PE data indicate strong orbital interactions between the diene and acetal moieties in 1. Different conformations have been evaluated by a joint MMP2 molecular mechanics and ab initio molecular orbital analysis, which shows 1 to prefer a slightly boat‐shaped conformation with the diene part being planar and the CH2 group placed considerably out‐of‐plane. The bicyclic acetals 2 and 3 show a frontier orbital picture similar to 1 superimposed with the characteristics of the CO and CC groups, respectively. The crystal structure of the keto‐acetal 2 was determined by an X‐ray analysis.
AB - The He(I) PE spectra of 1,3‐dioxepine (1) and the related bicyclic acetals 1,3,7,7‐tetramethyl‐2,11‐dioxabicyclo[4.41]undeca‐3,5‐dien‐10‐one (2) and 1,3,7,7‐tetramethyl‐10‐methylidene‐2,11‐dioxabicyclo[4.4.1]undeca‐3,5‐diene (3) have been recorded and analyzed. Interpretation of the PE data indicate strong orbital interactions between the diene and acetal moieties in 1. Different conformations have been evaluated by a joint MMP2 molecular mechanics and ab initio molecular orbital analysis, which shows 1 to prefer a slightly boat‐shaped conformation with the diene part being planar and the CH2 group placed considerably out‐of‐plane. The bicyclic acetals 2 and 3 show a frontier orbital picture similar to 1 superimposed with the characteristics of the CO and CC groups, respectively. The crystal structure of the keto‐acetal 2 was determined by an X‐ray analysis.
UR - http://www.scopus.com/inward/record.url?scp=84987493226&partnerID=8YFLogxK
U2 - 10.1002/hlca.19850680809
DO - 10.1002/hlca.19850680809
M3 - Journal article
AN - SCOPUS:84987493226
SN - 0018-019X
VL - 68
SP - 2148
EP - 2157
JO - Helvetica Chimica Acta
JF - Helvetica Chimica Acta
IS - 8
ER -