β-Tosylethylhydroxylamine: Preparation and Use as a Hydroxylamine Equivalent in Amidyl Radical-Olefin Cyclizations

Gerald D.  Artman III; Jacob H.  Waldman; Steven M.  Weinreb

doi:10.1055/s-2002-34371

PAPER

β-Tosylethylhydroxylamine: Preparation and Use as a Hydroxylamine Equivalent in Amidyl Radical-Olefin Cyclizations

Gerald D. Artman III, Jacob H. Waldman, Steven M. Weinreb*
Department of Chemistry, The Pennsylvania State University, University Park, Pennsylvania 16802, USA
Fax: +1(814)8638403; e-Mail: smw@chem.psu.edu;

Abstract

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Abstract

An efficient three-step procedure has been developed for synthesis of β-tosylethylhydroxylamine from commercially available starting material. This compound forms hydroxamic acids which undergo amidyl radical-olefin cyclizations promoted by diethyl chlorophosphite to give functionalized β-tosylethyl-protected lactams, which can be deprotected under mild basic conditions.

Key words

lactams - radical reactions - protecting groups - cyclizations

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References

For general reviews of nitrogen radical-olefin cyclizations see:

<A NAME="RC01202SS-1A">1a</A> Esker JL. Newcomb M. Adv. Heterocycl. Chem. 1993, 58: 1

<A NAME="RC01202SS-1B">1b</A> Zard SZ. Synlett 1996, 1148

<A NAME="RC01202SS-1C">1c</A> Fallis AG. Brinza IM. Tetrahedron 1997, 53: 17543

For some recent reports of the generation of amidyl radicals from hydroxamic acid derivatives see:

<A NAME="RC01202SS-2A">2a</A> Clark AJ. Peacock JL. Tetrahedron Lett. 1998, 39: 1265

<A NAME="RC01202SS-2B">2b</A> Clark AJ. Filik RP. Peacock JL. Thomas GH. Synlett 1999, 441

<A NAME="RC01202SS-2C">2c</A> Clark AJ. Deeth RJ. Samuel CJ. Wongtap H. Synlett 1999, 444

<A NAME="RC01202SS-3A">3a</A> Lin X. Stien D. Weinreb SM. Tetrahedron. Lett. 2000, 41: 2333

<A NAME="RC01202SS-3B">3b</A> Lin X. Artman GD. Stien D. Weinreb SM. Tetrahedron 2001, 57: 8779

<A NAME="RC01202SS-4A">4a</A> Richey HG. Farkas J. J. Org. Chem. 1987, 52: 479

<A NAME="RC01202SS-4B">4b</A> Sun P. Weinreb SM. Shang M. J. Org. Chem. 1997, 62: 8604

<A NAME="RC01202SS-4C">4c</A> Cogan DA. Liu G. Kim K. Backes BJ. Ellman JA. J. Am. Chem. Soc. 1998, 120: 8011

<A NAME="RC01202SS-4D">4d</A> Gontcharov AV. Liu H. Sharpless KB. Org. Lett. 1999, 1: 783

<A NAME="RC01202SS-5A">5a</A> Bleeker IP. Engberts JBFN. Recl. Trav. Chim. Pays-Bas 1979, 120

<A NAME="RC01202SS-5B">5b</A> Bouma WJ. Engberts JBFN. J. Org. Chem. 1976, 41: 143

<A NAME="RC01202SS-5C">5c</A> Hovius K. Engberts JBFN. Tetrahedron Lett. 1972, 13: 181

<A NAME="RC01202SS-5D">5d</A> Heesing A. Homann WK. Mullers W. Chem. Ber. 1980, 113: 152

<A NAME="RC01202SS-5E">5e</A> Banks MR. Hudson RF. J. Chem. Soc., Perkin Trans. 2 1986, 1211

<A NAME="RC01202SS-6">6</A> Banks MR. Hudson RF. J. Chem. Soc., Perkin Trans. 2 1989, 463

We have made a few attempts to effect such a cyclization but without success.

<A NAME="RC01202SS-8A">8a</A> DiPietro D. Borzilleri RM. Weinreb SM. J. Org. Chem. 1994, 59: 5856

<A NAME="RC01202SS-8B">8b</A> Borzilleri RM. Weinreb SM. Parvez M. J. Am. Chem. Soc. 1995, 117: 10905

For examples of TSE protection of nitrogen functionality in various heteroaromatics see:

<A NAME="RC01202SS-9A">9a</A> Faubl H. Tetrahedron Lett. 1979, 491

<A NAME="RC01202SS-9B">9b</A> Gonzalez C. Greenhouse R. Tallabs R. Muchowski JM. Can. J. Chem. 1983, 61: 1697

<A NAME="RC01202SS-9C">9c</A> Rao AKSB. Rao CG. Singh BB. Synth. Commun. 1994, 24: 341

<A NAME="RC01202SS-9D">9d</A> Bashford KE. Cooper AL. Kane PD. Moody CJ. Tetrahedron Lett. 2002, 43: 135

Attempted PCC oxidation of alcohol 6 led only to the dimeric ester i. Swern oxidation led to a complex mixture (Figure). Cf [11]

<A NAME="RC01202SS-11">11</A> Stacey FW. Sauer JC. McKusick BC. J. Am. Chem. Soc. 1959, 81: 987

<A NAME="RC01202SS-12">12</A> Borch RF. Bernstein MD. Durst HD. J. Am. Chem. Soc. 1971, 93: 2897

<A NAME="RC01202SS-13">13</A> This reaction might involve nucleophilic addition to an intermediate vinylnitroso compound: Gilchrist TL. Chem. Soc. Rev. 1983, 11: 53 ; and references cited

<A NAME="RC01202SS-14A">14a</A> For 3,3-dimethylpent-4-enoic acid and 3-methylpent-4-enoic acid see: Li W. Hanau CE. d’Avignon A. Moeller KD. J. Org. Chem. 1995, 60: 8155

<A NAME="RC01202SS-14B">14b</A> For 5-methylhex-4-enoic acid see: Curran DP. Yu H. Liu H. Tetrahedron 1994, 50: 7343

<A NAME="RC01202SS-14C">14c</A> For 2-methylpent-4-enoic acid see: Battersby AR. Westwood SW. J. Chem. Soc., Perkin Trans. 1 1987, 1679