SVIBOR - Project code: 1-07-006

MINISTRY OF SCIENCE AND TECHNOLOGY

Strossmayerov trg 4, HR - 10000 ZAGREB
tel.: +385 1 459 44 44, fax: +385 1 459 44 69
E-mail: ured@znanost.hr

SVIBOR

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Project code: 1-07-006


PI,SIGMA AND EXTENDED PI-PARTICIPATION IN SOLVOLYSIS


Main researcher: HUMSKI, KREŠIMIR (16812)


Assistants
Type of research: basic
Duration from: 01/01/91. to 12/31/94.
Papers on project (total): 14
Papers on project quoted in Current Contents: 5
Institution name: Farmaceutsko-biokemijski fakultet, Zagreb (6)
Department/Institute: Department of Chemistry Division of Organic Chemistry
Address: Ante Kovačića 1, 41000 Zagreb
City: 10000 - Zagreb, Croatia
Communication
Phone: 385 (41) 446 471
Fax: 385 (41) 445 117
E-mail: borcic@olimp.irb.hr
E-mail: kronja@olimp.irb.hr
E-mail: humski@nana.pharma.hr
Summary: a) Cyclopropylmethyl and cyclobutyl derivatives solvolyze by way of very complicated structures. We expect that by monitoring the percentage of internal rearrangements in various solvents to gain information of factors that influence the formation of the intimate ion pair, as well as its conversion to products. b) The single evidence that squalenyl chloride solvolyze with extended pi-paricipation is the secondary kinetic deuterium isotope effect. In order to support the existence of extended pi-participation we intend to prepare and solvolyze related supstrates with differently substituted phenyl groups, and calculate the rho,sigma-correlations.

Keywords: a) cyclopropylmethyl mesilate, internal ion pair b) biomimetic reaction, solvolysis mechanism, extended pi-participation, sigma/rho-correlation

Research goals: a) The aim of investigation is to establish the influence of nucleofilicity and ionization power of the solvent on the carbocation (internal ion pair) reactivity in solvolysis of cyclopropylmethyl (cyclobutyl) derivatives. These results may be important for understanding the structure of intermediates in these reactions, as well as for understanding the reactivity of internal ion pairs in general. b) In nature the squalene derivative cyclization leads to steroid hormones, but the mechanism is still unknown. In previous papers we demonstrated using deuterium kinetic isotope effects that squalenyl chloride in biomimetic conditions solvolyzes by way of extended pi-participation. Since it is the single proof of the mechanim, we also intend to prove it using rho,sigma- correlations.

COOPERATION - PROJECTS


  1. Name of project: JF 825 NSF Mechanism od Biomimetic Cationic Cyclizations
    Name of institution: Department of Chemistry, Indiana University
    City: 47405 - Bloomington, Indiana, U.S.A

COOPERATION - INSTITUTIONS


  1. Name of institution: Institut Ruđer Bosković
    Type of institution: University/Faculty
    City: 10000 - Zagreb, Croatia

  2. Name of institution: Department of Chemistry, Yale University
    Type of institution: University/Faculty
    City: 06511 - New Haven, Connecticut, U.S.A.

  3. Name of institution: Pridodoslovno-matematički fakultet
    Type of institution: University/Faculty
    City: 10000 - Zagreb, Croatia

  4. Name of institution: Department of Chemistry, University of Minnesota
    Type of institution: University/Faculty
    City: 55455 - Minneapolis, Minnesota, U.S.A.
Other information about the project.
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