2026-09-21T19:53:37Z https://www.ideals.illinois.edu/oai-pmh

oai:www.ideals.illinois.edu:2142/20783 2023-07-10 col_2142_5131 col_2142_14789 com_2142_5130 com_2142_14788 com_2142_8903

Beak, Peter Tollefson, Michael Brent 2011-05-07T12:49:09Z 2011-05-07T12:49:09Z 10000-01-01 1996 Double labeling has been used in conjuction with the endocyclic restriction test to show that transfers of phosphorus from oxygen to carbon in the conversions of 45 to 46, of 120 to 126, of 121 to 127 and of 122 to 128 proceed in an intramolecular fashion. The transfers of a chiral phosphorus atom in the conversions of 123 to 129, of 124 to 130 and of 125 to 131 proceed with retention of stereochemistry at phosphorus. These results rule out the classic in-line S$\rm\sb N$2 pathway and the geometrically equivalent in-line addition-elimination pathway for these endocyclic transfers of phosphorus. Initial apical attack followed by pseudorotation and elimination of the apical alkoxy leaving group is suggested for these nucleophilic substitutions at phosphorus. Application for the endocyclic restriction test to determine the geometry required for nucleophilic substitution at an oxenoid oxygen was attempted. A number of compounds were examined for their ability to react with molecular oxygen to form an oxenoid and carbanion within the same molecule. Oxygen incorporation was observed in a few cases, however, no products which can he definitively ascribed to oxenoid oxygen transfer were observed. Made available in DSpace on 2011-05-07T12:49:09Z (GMT). No. of bitstreams: 2 license.txt: 4922 bytes, checksum: 910b249b4beec47e7ab768910c8f966f (MD5) 9712461.pdf: 4826754 bytes, checksum: 721d408e78817b7b0d500406bd21ceb7 (MD5) Previous issue date: 1996 Item marked as restricted to the 'UIUC Users [automated]' Group (id=2) by Howard Ding (hding2@illinois.edu) on 2011-05-07T14:46:14Z Item is restricted indefinitely. Restriction data tranferred 2014-07-01T11:20:40-05:00 Original Data Group with Access UIUC Users [automated] Release Date: none Reason: ETDs are only available to UIUC Users without author permission ETDs are only available to UIUC Users without author permission U of I Only 9780591199437 AAI9712461 (UMI)AAI9712461 http://hdl.handle.net/2142/20783 eng Copyright 1996 Tollefson, Michael Brent Chemistry, Organic The endocyclic restriction test: (I) Determination of reaction pathways for the nucleophilic substitution at phosphorus by carbon. (II) Exploration of the reaction pathway of nucleophilic substitution at an oxenoid oxygen by carbon text Chemistry Chemistry University of Illinois at Urbana-Champaign Dissertation Ph.D.