Facile Aerobic Photo-Oxidative Synthesis of Phenacyl Iodides and Bromides from Styrenes Using I₂ or Aqueous HBr

Abstract

We report a useful method for facile synthesis of phenacyl iodides and bromides from styrene derivatives by aerobic photo-oxidation using I₂ or 48% aqueous HBr in the presence of water.

aerobic - photo-oxidation - phenacyl iodide - phenacyl bromide - styrene

References and Notes

<A NAME="RU05510ST-1">1</A> For a recent review, see: Takami K. Usugi S.-I. Yorimitsu H. Oshima K. Synthesis  2005,  824 

<A NAME="RU05510ST-2A">2a</A> Hantzsch A. Weber H. Ber. Dtsch. Chem. Ges.  1887,  20:  3118 

<A NAME="RU05510ST-2B">2b</A> Baldwin JE. Fryer AM. Pritchard GJ.
J. Org. Chem.  2001,  66:  2588 

<A NAME="RU05510ST-3A">3a</A> Ma S. Lu L. Lu P. J. Org. Chem.  2005,  70:  1063 

<A NAME="RU05510ST-3B">3b</A> Lu L. Lu P. Ma S. Eur. J. Org. Chem.  2007,  676 

<A NAME="RU05510ST-4">4</A> Huang Z.-Z. Tang Y. J. Org. Chem.  2002,  67:  5320 

<A NAME="RU05510ST-5A">5a</A> Forlani L. Synthesis  1980,  487 

<A NAME="RU05510ST-5B">5b</A> Choi HY. Chi DY. Org. Lett.  2003,  5:  411 

<A NAME="RU05510ST-5C">5c</A> Diwu Z. Beachdel C. Klaubert DH. Tetrahedron Lett.  1998,  39:  4987 

<A NAME="RU05510ST-5D">5d</A> Attanasi OA. Berretta S. Favi G. Filippone P. Mele G. Moscatelli G. Saladino R. Org. Lett.  2006,  8:  4291 

<A NAME="RU05510ST-5E">5e</A> Bekaert A. Provot O. Rasolojaona O. Alami M. Brion J.-D. Tetrahedron Lett.  2005,  46:  4187 

<A NAME="RU05510ST-6">6</A> Tanemura K. Suzuki T. Nishida Y. Satsumabayashi K. Horaguchi T. Chem. Commun.  2004,  470 

<A NAME="RU05510ST-7">7</A> King LC. Ostrum GK. J. Org. Chem.  1964,  29:  3459 

<A NAME="RU05510ST-8">8</A> Podgoršek A. Stavber S. Zupan M. Iskra J. Green Chem.  2007,  9:  1212 

<A NAME="RU05510ST-9">9</A> Rao MLN. Jadhav DN. Tetrahedron Lett.  2006,  47:  6883 

<A NAME="RU05510ST-10">10</A> Pavlinac J. Zupan M. Stavber S. Org. Biomol. Chem.  2007,  5:  699 

<A NAME="RU05510ST-11">11</A> Yin G. Gao M. She N. Hu S. Wu A. Pan Y. Synthesis  2007,  3113 

<A NAME="RU05510ST-12">12</A> Bekaert A. Barberan O. Gervais M. Brion J.-D. Tetrahedron Lett.  2000,  41:  2903 

<A NAME="RU05510ST-13">13</A> Jereb M. Stavber S. Zupan M. Synthesis  2003,  853 

<A NAME="RU05510ST-14">14</A> Bras GL. Provot O. Bekaert A. Peyrat J.-F. Alami M. Brion J.-D. Synthesis  2006,  1537 

<A NAME="RU05510ST-15">15</A> Horiuchi CA. Kiji S. Bull. Chem. Soc. Jpn.  1997,  70:  421 

<A NAME="RU05510ST-16">16</A> Lee JC. Bae YH. Synlett  2003,  507 

<A NAME="RU05510ST-17A">17a</A> Cardillo G. Shimizu M. J. Org. Chem.  1977,  42:  4268 

<A NAME="RU05510ST-17B">17b</A> D’Ascoli R. D’Auria M. Nucciarelli L. Piancatelli G. Scattri A. Tetrahedron Lett.  1980,  21:  4521 

<A NAME="RU05510ST-17C">17c</A> Moriuchi T. Yamaguchi M. Kikushima K. Hirao T. Tetrahedron Lett.  2007,  48:  2667 

<A NAME="RU05510ST-18A">18a</A> Evans RD. Schauble JH. Synthesis  1986,  727 

<A NAME="RU05510ST-18B">18b</A> Yadav JS. Subba Reddy BV. Singh AP. Basak AK. Tetrahedron Lett.  2008,  49:  5880 

<A NAME="RU05510ST-18C">18c</A> Moorthy JN. Senapati K. Singhal N. Tetrahedron Lett.  2009,  50:  2493 

<A NAME="RU05510ST-19A">19a</A> Kageyama T. Tobito Y. Katoh A. Ueno Y. Okawara M. Chem. Lett.  1983,  12:  1481 

<A NAME="RU05510ST-19B">19b</A> Patil RD. Joshi G. Adimurthy S. Ranu BC. Tetrahedron Lett.  2009,  50:  2529 

<A NAME="RU05510ST-20">20</A> Nakayama H. Itoh A. Tetrahedron Lett.  2007,  48:  1131 

<A NAME="RU05510ST-21">21</A>

Typical Procedure for the Synthesis of 4- tert -Butylphenacyl Iodide (2, Table 3, Entry 1)
A solution of 4-tert-butylstyrene (1, 0.3 mmol), I₂ (0.18 mmol), and H₂O (80 µL) in dry EtOAc (3 mL) in a Pyrex test tube, purged with an O₂ balloon, was stirred and irradiated externally with four 22 W fluorescent lamps for 10 h. The reaction mixture was washed with aq Na₂S₂O₃ and brine, and concentrated in vacuo. Purification of the crude product by PTLC (hexane-EtOAc = 5:1) provided 4-tert-butylphenacyl iodide (R _f  = 0.50, 77.0 mg, 85%).
4- tert -Butylphenacyl Iodide (2) ^¹H NMR (500 MHz, CDCl₃): δ = 7.93 (d, J = 8.8 Hz, 2 H), 7.49 (d, J = 8.8 Hz, 2 H), 4.34 (s, 2 H), 1.35 (s, 9 H). ^¹³C NMR (125 MHz, CDCl₃): δ = 192.6, 157.8, 131.0, 129.1, 125.9, 35.3, 31.2, 1.9. HRMS (EI⁺): m/z calcd for C₁₂H₁₅OI [M⁺]: 302.0168; found: 302.0174.
2-Methylphenacyl Iodide (11) ^¹H NMR (500 MHz, CDCl₃): δ = 7.67 (d, J = 7.4 Hz, 1 H), 7.41 (t, J = 7.4 Hz, 1 H), 7.29-7.25 (m, 2 H), 4.33 (s, 2 H), 2.51 (s, 3 H). ^¹³C NMR (125 MHz, CDCl₃): δ = 195.8, 139.9, 134.4, 132.3, 128.9, 125.8, 21.5, 5.8. MS (EI⁺): m/z (%) = 260 [M⁺], 133, 119 (100), 105, 91, 65.
2-Iodo-1-(2-naphthalenyl)ethanone (23) ^¹H NMR (500 MHz, CDCl₃): δ = 8.51 (s, 1 H), 8.03-7.96 (m, 2 H), 7.91-7.87 (m, 2 H), 7.63-7.55 (m, 2 H), 4.48 (s, 2 H). ^¹³C NMR (125 MHz, CDCl₃): δ = 193.0, 135.9, 132.5, 131.1, 130.9, 129.8, 129.1, 128.9, 128.0, 127.1, 124.5, 1.9. HRMS (EI⁺): m/z calcd for C₁₂H₉OI [M⁺]: 295.9699; found: 295.9693.
2-Iodo-1-(2-pyridinyl)ethanone (26) ^¹H NMR (500 MHz, CDCl₃): δ = 8.70 (d, J = 4.0 Hz, 1 H), 8.10 (d, J = 6.8 Hz, 1 H), 7.89-7.86 (m, 1 H), 7.53-7.50 (m, 1 H), 4.69 (s, 2 H). ^¹³C NMR (125 MHz, CDCl₃): δ = 194.5, 150.8, 149.2, 137.2, 127.8, 123.0, 1.9. HRMS (EI⁺): m/z calcd for C₇H₆NOI [M⁺]: 246.9494; found: 246.9503.
4- tert -Butylphenacyl Bromide (3) ^¹H NMR (500 MHz, CDCl₃): δ = 7.92 (d, J = 8.8 Hz, 2 H), 7.50 (d, J = 8.8 Hz, 2 H), 4.43 (s, 2 H), 1.35 (s, 9 H). ^¹³C NMR (125 MHz, CDCl₃): δ = 191.0, 158.0, 131.4, 129.0, 126.0, 35.3, 31.3, 31.1. HRMS (EI⁺): m/z calcd for C₁₂H₁₅OBr [M⁺]: 254.0306; found: 254.0314.
2-Bromo-1-(2-pyridinyl)ethanone (27) ^¹H NMR (500 MHz, CDCl₃): δ = 8.70 (d, J = 4.6 Hz, 1 H), 8.11 (d, J = 8.0 Hz, 1 H), 7.90-7.87 (m, 1 H), 7.54-7.52 (m, 1 H), 4.87 (s, 2 H). ^¹³C NMR (125 MHz, CDCl₃): δ = 192.6, 151.5, 149.3, 137.3, 127.9, 122.8, 32.6. HRMS (EI⁺): m/z calcd for C₇H₆NOBr [M⁺]: 198.9633; found: 198.9641.
2-Bromo-1-phenyl-1-propanone (30) ^¹H NMR (500 MHz, CDCl₃): δ = 8.04-8.02 (m, 2 H), 7.61-7.58 (m, 1 H), 7.51-7.48 (m, 2 H), 5.30 (q, J = 6.9 Hz, 1 H), 1.91 (d, J = 6.9 Hz, 3 H). ^¹³C NMR (125 MHz, CDCl₃): δ = 193.4, 134.1, 133.8, 129.0, 128.9, 41.5, 20.2. MS (EI⁺): m/z (%) = 212 [M⁺], 105 (100), 77, 51.
1-Bromo-2-dodecanone (36) ^¹H NMR (500 MHz, CDCl₃): δ = 3.89 (s, 2 H), 2.65 (t, J = 7.5 Hz, 2 H), 1.63-1.58 (m, 2 H), 1.29-1.26 (m, 14 H), 0.88 (t, J = 6.9 Hz, 3 H). ^¹³C NMR (125 MHz, CDCl₃): δ = 202.4, 40.0, 34.4, 32.0, 29.6, 29.5, 29.4, 29.4, 29.1, 24.0, 22.8, 14.2. LRMS (FAB⁺): m/z (%) = 263 [M⁺ + 1], 120, 107, 89, 77, 65, 55, 41.

<A NAME="RU05510ST-22A">22a</A> Sugai T. Itoh A. Tetrahedron Lett.  2007,  48:  9096 

<A NAME="RU05510ST-22B">22b</A> Hirashima S. Itoh A. Photochem. Photobiol. Sci.  2007,  6:  521