TY - JOUR
T1 - Quantum chemical characterization of the cyclization of the neocarzinostatin chromophore to the 1,5-didehydroindene biradical
AU - Cramer, Christopher J.
AU - Squires, Robert R.
PY - 1999/7/29
Y1 - 1999/7/29
N2 - (equation presented) Quantum mechanical calculations have been carried out for the cyclization of the neocarzinostatin chromophore cyclonona-1,2,3,7-tetraen-5-yne to 1,5-didehydroindene. The 298 K reaction activation enthalpy, exothermicity, and singlet-triplet splitting (H0) of the product biradical are predicted to be 17.8, 1.2, and -6.4 kcal/mol, respectively, at levels of theory showing near-quantitative agreement with experiment for the analogous cyclizations of hex-3-ene-1,5-diyne and hepta-1,2,4-trien-6-yne. Factors controlling differences in the Myers-Saito cyclization compared to the Bergman cyclization are analyzed.
AB - (equation presented) Quantum mechanical calculations have been carried out for the cyclization of the neocarzinostatin chromophore cyclonona-1,2,3,7-tetraen-5-yne to 1,5-didehydroindene. The 298 K reaction activation enthalpy, exothermicity, and singlet-triplet splitting (H0) of the product biradical are predicted to be 17.8, 1.2, and -6.4 kcal/mol, respectively, at levels of theory showing near-quantitative agreement with experiment for the analogous cyclizations of hex-3-ene-1,5-diyne and hepta-1,2,4-trien-6-yne. Factors controlling differences in the Myers-Saito cyclization compared to the Bergman cyclization are analyzed.
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U2 - 10.1021/ol990014d
DO - 10.1021/ol990014d
M3 - Article
AN - SCOPUS:0001329138
SN - 1523-7060
VL - 1
SP - 215
EP - 218
JO - Organic Letters
JF - Organic Letters
IS - 2
ER -