STEREOCHEMICAL STUDIES ON HEMIORTHOTHIOAMIDE TETRAHEDRAL INTERMEDIATES
Abstract
A study of the stereochemistry of hemiorthothioamide tetrahedral intermediates of the type RC(OR')(NR(,2))(SH) {22} was undertaken in order to assess the importance of the stereoelectronic effects in the breakdown of {22}. These intermediates were generated by the ion-ion combination of SH('(CRMINUS)) ion and imidate salts of the general type R(OR)C = N('(CRPLUS))R(,2) BF(,4)('(CRMINUS)). The breakdown of {22} may occur by cleavage of either the C-N or the C-O bond. The kinetic products (C-N cleavage) were in general formed at low temperature, their reactivity precluding their isolation. Two major procedures for their trapping were tried: (1) The precooled trapping agents were added after the sulfhydrolysis is over; (2) the sulfhydrolysis was carried out in the presence of the trapping agent. The second method, in general, proved to be a superior way of trapping the products under kinetic control. The breakdown of tetrahedral intermediates from imidate salts of the type oxazolinium, oxazinium (34a-d), N,N-dimethyliminolactonium (46a-e) and N-methyl-O-methyllactamium (64a,b) salts, seemed to be in conformity with the stereoelectronic theory. The low reactivity of bicyclic imidate salt 81 precluded the obtention of the corresponding kinetic products. A secondary stereoelectronic effect was suggested to assist the breakdown of tetrahedral intermediate {33} resulting from bicyclic imidate 92. A novel intramolecular O (--->) N thioacyl transfer and a preparative scale synthesis of 5-, 6- and 7-membered thionolactones are reported.
Subject Area
Organic chemistry
Recommended Citation
NADER, RANDA B, "STEREOCHEMICAL STUDIES ON HEMIORTHOTHIOAMIDE TETRAHEDRAL INTERMEDIATES" (1980). ETD Collection for Fordham University. AAI8020077.
https://research.library.fordham.edu/dissertations/AAI8020077
