"Front Matter". In: Organosilanes in Radical Chemistry - Index of

More documents

Recommendations

Info

Application to Tandem and Cascade Radical Reactions 179 7.88) [101]. On the other hand, the analogous iodo derivative 81 with (TMS) 3SiH at room temperature afforded a linear fused five-membered carbocycle in two isomeric forms and with an overall yield of 74 % (Reaction 7.89) [102]. In this case, the cascade proceeds through 5-exo, 5-exo, and5-exo modes of cyclization. E E I CO 2 Me 81 CO 2 Me I (TMS) 3SiH AIBN, 80 �C CO 2 Me 79 80, 77% (TMS) 3 SiH Et 3 B, r.t. E = CO 2 Me E H E H E + E H H CO2Me H H CO2Me 42% 32% (7.88) (7.89) Radical cascade starting from bromomethyldimethylsilyl propargyl ethers has been utilized in a remarkable way [103–105]. Reduction of the bromide 82 in the presence of (TMS) 3SiH and subsequent treatment with MeLi produced the functionalized cyclopentanone precursor 83 as a single diastereomer (Scheme 7.11). The formation of 83 has been explained by a series of reactions, indicated in Scheme 7.11, involving a 5-exo cyclization of the initial a-silyl alkyl radical (not shown) followed by a [1,5]-radical translocation of the generated s-type vinyl radical onto the proximal acetal function and a final 5-exo cyclization process. Stereoselective hydrogen abstraction, dependent on the steric bulkiness of the hydrogen donor, followed by MeLi-induced opening of the Si w O bond afforded the final product. The introduction of different substituents on the skeleton, as in compound 84 resulted in a completely different reaction pattern (Reaction 7.90) [104,105]. In this case, the intermediate vinyl radical (cf. Scheme 7.11) underwent a [1,5]-hydrogen abstraction from the non-activated C w H bond of the proximal isopropyl group. Furthermore, the resulting primary alkyl radical underwent a unique, stereoselective 5-endo cyclization onto the adjacent double bond to generate a tertiary radical, which is a precursor of the highly substituted cyclopentanols 85 and 86.
180 Consecutive Radical Reactions O Si O H O Me Me O Si Br Me Me O O 1. (TMS) 3SiH, AIBN, 80 �C 2. MeLi O 1,5-H shift O Si H O 5-exo-trig Me Me O H HO Me 3 Si 82 83, 92% Scheme 7.11 Some details of a radical cascade reaction i-Pr i-Pr O Si Br Me Me 84 Bu-t 1. (TMS) 3 SiH, AIBN, 80 �C 2. MeLi H HO Me i-Pr Me3Si 85 + H Me i-Pr HO Me3Si H 86 95%, 85:86 = 90:10 H O Me Si Me O O O (7.90) A highly efficient route to azacoumarins has been obtained by treatment of compounds 87 with (TMS) 3SiH under standard experimental conditions (Reaction 7.91) [69]. The mechanism based on an unusual double intramolecular 1,5-ipso and 1,6-ipso substitution with the final ejection of MeO: radical. MeO R Br O 87 O N OMe (TMS) 3SiH AIBN, 80 �C R = H R = OMe MeO R O O N 62% 75% (7.91)
Page 1 and 2:
Organosilanes in Radical Chemistry
Page 3 and 4:
DEDICATION To my parents XrZstoB an
Page 5 and 6:
viii Contents 3.6 Hydrogen Atom: An
Page 7 and 8:
PREFACE A large number of papers de
Page 9 and 10:
ACKNOWLEDGEMENTS I thank Keith U. I
Page 11 and 12:
2 Formation and Structures of Silyl
Page 13 and 14:
Page 15 and 16:
Page 17 and 18:
Page 19 and 20:
10 Formation and Structures of Sily
Page 21 and 22:
Page 23 and 24:
Page 25 and 26:
Page 27 and 28:
2 Thermochemistry 2.1 GENERAL CONSI
Page 29 and 30:
Bond Dissociation Enthalpies 21 Tab
Page 31 and 32:
Bond Dissociation Enthalpies 23 2.2
Page 33 and 34:
Ion Thermochemistry 25 Table 2.4 Re
Page 35 and 36:
Ion Thermochemistry 27 Table 2.5 El
Page 37 and 38:
References 29 3. Goumri, A., Yuan,
Page 39 and 40:
32 Hydrogen Donor Abilities of Sili
Page 41 and 42:
Page 43 and 44:
Page 45 and 46:
Page 47 and 48:
Page 49 and 50:
Page 51 and 52:
Page 53 and 54:
Page 55 and 56:
4 Reducing Agents 4.1 GENERAL ASPEC
Page 57 and 58:
General Aspects of Radical Chain Re
Page 59 and 60:
Tris(trimethylsilyl)silane 53 Therm
Page 61 and 62:
Tris(trimethylsilyl)silane 55 4.3.1
Page 63 and 64:
Tris(trimethylsilyl)silane 57 A goo
Page 65 and 66:
Tris(trimethylsilyl)silane 59 C(O)C
Page 67 and 68:
Tris(trimethylsilyl)silane 61 radic
Page 69 and 70:
Tris(trimethylsilyl)silane 63 86% y
Page 71 and 72:
Tris(trimethylsilyl)silane 65 RO RO
Page 73 and 74:
Tris(trimethylsilyl)silane 67 O AcO
Page 75 and 76:
Tris(trimethylsilyl)silane 69 Tris(
Page 77 and 78:
Other Silicon Hydrides 71 The reduc
Page 79 and 80:
Other Silicon Hydrides 73 The decre
Page 81 and 82:
Other Silicon Hydrides 75 Ph MeS O
Page 83 and 84:
Other Silicon Hydrides 77 Table 4.6
Page 85 and 86:
Silicon Hydride / Thiol Mixture 79
Page 87 and 88:
Silylated Cyclohexadienes 81 and (4
Page 89 and 90:
References 83 34. Kawashima, E., Uc
Page 91 and 92:
References 85 104. Gimisis, T., Bal
Page 93 and 94:
88 Addition to Unsaturated Bonds te
Page 95 and 96:
90 Addition to Unsaturated Bonds ap
Page 97 and 98:
92 Addition to Unsaturated Bonds 5.
Page 99 and 100:
94 Addition to Unsaturated Bonds R
Page 101 and 102:
96 Addition to Unsaturated Bonds Ph
Page 103 and 104:
98 Addition to Unsaturated Bonds EP
Page 105 and 106:
100 Addition to Unsaturated Bonds 5
Page 107 and 108:
102 Addition to Unsaturated Bonds T
Page 109 and 110:
104 Addition to Unsaturated Bonds R
Page 111 and 112:
106 Addition to Unsaturated Bonds a
Page 113 and 114:
Page 115 and 116:
110 Addition to Unsaturated Bonds S
Page 117 and 118:
112 Addition to Unsaturated Bonds T
Page 119 and 120:
114 Addition to Unsaturated Bonds I
Page 121 and 122:
Page 123 and 124:
Page 125 and 126:
120 Unimolecular Reactions 1 Si(H)M
Page 127 and 128:
122 Unimolecular Reactions t-Bu t-B
Page 129 and 130:
124 Unimolecular Reactions MeO Si O
Page 131 and 132:
126 Unimolecular Reactions t-Bu t-B
Page 133 and 134: 128 Unimolecular Reactions R 1 R 2
Page 135 and 136: 130 Unimolecular Reactions From the
Page 137 and 138: 132 Unimolecular Reactions rearrang
Page 139 and 140: 134 Unimolecular Reactions H 3 C +
Page 141 and 142: 136 Unimolecular Reactions Br O Si(
Page 143 and 144: 138 Unimolecular Reactions R3Si C C
Page 145 and 146: 140 Unimolecular Reactions Me3Si O
Page 147 and 148: 142 Unimolecular Reactions 43. Albe
Page 149 and 150: 144 Consecutive Radical Reactions c
Page 151 and 152: 146 Consecutive Radical Reactions O
Page 153 and 154: 148 Consecutive Radical Reactions a
Page 155 and 156: 150 Consecutive Radical Reactions d
Page 157 and 158: 152 Consecutive Radical Reactions T
Page 159 and 160: 154 Consecutive Radical Reactions M
Page 161 and 162: 156 Consecutive Radical Reactions F
Page 167 and 168: 162 Consecutive Radical Reactions i
Page 169 and 170: 164 Consecutive Radical Reactions A
Page 173 and 174: 168 Consecutive Radical Reactions r
Page 175 and 176: 170 Consecutive Radical Reactions E
Page 179 and 180: 174 Consecutive Radical Reactions A
Page 181 and 182: 176 Consecutive Radical Reactions P
Page 183: 178 Consecutive Radical Reactions f
Page 187 and 188: 182 Consecutive Radical Reactions 1
Page 189 and 190: 184 Consecutive Radical Reactions 8
Page 191 and 192: 186 Silyl Radicals in Polymers and
Page 225 and 226: 220 List of Abbreviations PED photo
Page 227 and 228: 222 Index Carbonyl sulfide 111 Carb
Page 229 and 230: 224 Index Organosilicon boranes 2,
Page 231 and 232: 226 Index Triethylsilane as mediato
show all

"Front Matter". In: Organosilanes in Radical Chemistry - Index of

You also want an ePaper? Increase the reach of your titles

Delete template?

Save as template?