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A Kinetic Approach to the Mechanism of Cationic Polyolefinic Cyclization. Simple and Extended π-Participation

Stanko Borčić ; Faculty of Pharmacy and Biochemistry, University of Zagreb, A. Kovačića 1, P. O. Box 156, 41000 Zagreb, Croatia
Olga Kronja ; Faculty of Pharmacy and Biochemistry, University of Zagreb, A. Kovačića 1, P. O. Box 156, 41000 Zagreb, Croatia
Krešimir Humski ; Faculty of Pharmacy and Biochemistry, University of Zagreb, A. Kovačića 1, P. O. Box 156, 41000 Zagreb, Croatia

Puni tekst: engleski, pdf (40 MB) str. 171-188 preuzimanja: 109* citiraj
APA 6th Edition
Borčić, S., Kronja, O. i Humski, K. (1994). A Kinetic Approach to the Mechanism of Cationic Polyolefinic Cyclization. Simple and Extended π-Participation. Croatica Chemica Acta, 67 (2), 171-188. Preuzeto s https://hrcak.srce.hr/136883
MLA 8th Edition
Borčić, Stanko, et al. "A Kinetic Approach to the Mechanism of Cationic Polyolefinic Cyclization. Simple and Extended π-Participation." Croatica Chemica Acta, vol. 67, br. 2, 1994, str. 171-188. https://hrcak.srce.hr/136883. Citirano 27.02.2021.
Chicago 17th Edition
Borčić, Stanko, Olga Kronja i Krešimir Humski. "A Kinetic Approach to the Mechanism of Cationic Polyolefinic Cyclization. Simple and Extended π-Participation." Croatica Chemica Acta 67, br. 2 (1994): 171-188. https://hrcak.srce.hr/136883
Harvard
Borčić, S., Kronja, O., i Humski, K. (1994). 'A Kinetic Approach to the Mechanism of Cationic Polyolefinic Cyclization. Simple and Extended π-Participation', Croatica Chemica Acta, 67(2), str. 171-188. Preuzeto s: https://hrcak.srce.hr/136883 (Datum pristupa: 27.02.2021.)
Vancouver
Borčić S, Kronja O, Humski K. A Kinetic Approach to the Mechanism of Cationic Polyolefinic Cyclization. Simple and Extended π-Participation. Croatica Chemica Acta [Internet]. 1994 [pristupljeno 27.02.2021.];67(2):171-188. Dostupno na: https://hrcak.srce.hr/136883
IEEE
S. Borčić, O. Kronja i K. Humski, "A Kinetic Approach to the Mechanism of Cationic Polyolefinic Cyclization. Simple and Extended π-Participation", Croatica Chemica Acta, vol.67, br. 2, str. 171-188, 1994. [Online]. Dostupno na: https://hrcak.srce.hr/136883. [Citirano: 27.02.2021.]

Sažetak
This review deals with the mechanism of the biomimetic olefinic cationic polycyclizations considering relative rate effects, activation parameters, substituent rate effects, a, p correlation and secondary deuterium kinetic isotope effects (KIE) in solvolysis, obtained with tertiary and benzylic substrates comprising one, two or more double bonds, respectively, sited at the same positions as in the natural precursor (C-5, C-9, C-13). Kinetic behaviour of substrates with one double bond at position 5 (models for mono- cyclization) which are structurally related to structures 16U and 22U suggests that the formation of the first cyclohexane ring is a concerted process with some exceptions (16U with p-OCH3). In solvolysis of chlorides with double bonds at positions 5 and 9 (28 and 29U) extended it-parcipation occurs, i.e. both double bonds of the aliphatic chain are involved in the rate determining step. Substrastes with more then two double bonds (30U and 31U) solvolyze by way of extended 7i-participation. It remains unclear if two or three double bonds are involved. The paper also shows clear evidence that the magnitude of 3-deuterium secondary KIE are the most sensitive probe for neighboring group participation.

Hrčak ID: 136883

URI
https://hrcak.srce.hr/136883

Posjeta: 209 *