Synthesis of Polysubstituted Germoles and Benzogermoles Using a Substoichiometric Amount of Diisobutylaluminum Hydride

Abstract

We developed a synthetic route to unsymmetrically polysubstituted germoles bearing different substituents from 1hydrogermyl-4-silyl-1,3-enynes. The reaction proceeded with 0.5 equiv of diisobutylaluminum hydride. Various 2-silylgermoles including benzogermoles were obtained in good to excellent yields. 2-Germylbenzogermoles could be also successfully synthesized from 1-hydrogermyl-4-germyl-1,3-enynes under the same reaction conditions.

One-Pot Direct Synthesis of Siloles from 1-Bromo-2-silylethynylbenzenes or 1-Bromo-4-silyl-1,3-enynes

“…Colorless liquid [111 mg, 0.277 mmol, 59% yield from 1a (120 mg, 0.473 mmol)]; 1 H NMR (300 MHz, CDCl 3 ) δ 7.71 (d, J = 0.6 Hz, 1H), 7.60 (dd, J = 6.9, 0.9 Hz, 1H), 7.57–7.53 (m, 4H), 7.41–7.31 (m, 8H), 7.25 (ddd, J = 6.6, 6.6, 2.4 Hz, 1H), 0.07 (s, 9H); 13 C { 1 H} NMR (75 MHz, CDCl 3 ) δ 154.9, 154.9, 149.2, 145.6, 139.7, 135.4, 134.8, 132.7, 129.6, 129.3, 128.3, 127.8, 125.4, −0.1. The spectral properties of this compound were in satisfactory agreement with those previously reported …”

“…The spectral properties of this compound were in satisfactory agreement with those previously reported. 23 1,5-Dihydro-1,1,5,5-tetraphenyl-2,6-bis(trimethylsilyl)-1,5-disilas-indacene (3m) [1966096−06−9]. White solid [89.2 mg, 0.140 mmol, 45% yield from 1k (135 mg, 0.316 mmol)]; Mp = 285.0− 286.0 °C; 1 H NMR (300 MHz, CDCl 3 ) δ 7.72 (s, 2H), 7.64−7.61 (m, 8H), 7.57 (s, 2H), 7.39−7.34 (m, 4H), 7.36−7.33 (m, 8H), 0.03 (s, 18H); 13 C { 1 H} NMR (125 MHz, CDCl 3 ) δ 159.0, 150.2, 143.9, 141.1, 135.6, 132.6, 130.0, 128.8, 128.0, −0.1; 29 Si { 1 H} NMR (99 MHz, CDCl 3 ) δ −0.13, 6.04.…”

Cu-Catalyzed Enantioselective Hydrogermylation: Asymmetric Synthesis of Unnatural β-Germyl α-Amino Acids

“…Furthermore, changing the metal catalyst into Cu­(OAc) still gave no reactivity in the hydrosilylation reaction between 2a and dihydrosilane 1a (Table , entry 5), while to our delight, the desired β-germyl α-amino acid product 3ba was obtained in 95% yield with 35% ee in the hydrogermylation reaction between 2a and dihydrogermane 1b (Table , entry 6). It is worth mentioning that, despite a number of hydrogermylation reactions having been reported, − to our knowledge, here we realized the first example of catalytic enantioselective hydrogermylation of alkenes.…”

Metal‐Catalyzed Haloalkynylation Reactions

“…show how invaluable halogenated (chlorinated) enynes are for synthetic organic chemistry. Haloenyes are crucial precursors for the synthesis of highly substituted five‐ and six‐membered heterocyclic ring systems like furans, [44] germoles, [45] phospholenes, [46] phospholes, [47] siloles, [48] thiophenes, [49] quinolines [50] and chromenes. [51] One recent example uses the Pd‐catalyzed[ 16 , 28 ] and the Au‐catalyzed bromoalkynylation [36] of alkynes for the synthesis of bromoenynes 45 , which deliver highly substituted thiophenes ( 60 and 61 ) via a chemoselective heterocyclization (Scheme 27 ).…”