Electrophilic Fluorodesilylation of Allenylmethylsilanes:  A Novel Entry to 2-Fluoro-1,3-dienes

Abstract

[reaction: see text] Various fluorodienes were prepared by treatment of the corresponding allenylmethylsilanes with Selectfluor. This is the first route to these compounds not based on the use of a fluorinated building block. The reaction allows the preparation of 2-fluoro-1,3-dienes with several substitution patterns, including di- and trisubstituted compounds.

Asymmetric Synthesis of (1,3‐Butadien‐2‐yl)methanols from Aldehydes via [1‐(Silylmethyl)allenyl]methanols

“…To illustrate the versatility of these intermediates, 2g was treated with NIS to give the iodinated adduct 4 (Scheme ) 8. Furthermore, {1‐[(trimethylsilyl)methyl]allenyl}methanols may be treated with other electrophiles such as Br 2 or Selectfluor ® to afford the corresponding halogenated derivatives 2j,9…”

Mechanistic Investigation of RhI–Catalyzed Cycloisomerization of Benzylallene-Internal Alkynes via C–H Activation

“…6 (Sigma-Aldrich) were employed for reactions. 4-(benzyloxy)but-2-ynol (S1e), 16 5-(hept-2-ynyl)-2,2-dimethyl-5-(prop-2-ynyl)-1,3-dioxane (S2f), 8i dimethyl 2-(hept-2-ynyl)-2-(prop-2-ynyl)malonate (S2a), 6 2-methyl-2-phenylpropanal, 17 2-methyl-2-(p-tolyl)propanal, 17 2-(4-chlorophenyl)-2-methylpropanal, 18 1, 137.4, 128.4, 128.1, 127.8, 80.8, 79.5, 78.3, 71.8, 71.2, 57.3, 56.5, 53.1, 23.0, 22.8 3, 83.9, 78.6, 73.6, 71.4, 56.7, 52.9, 30.8, 22.8-22.2 (m), 21.7, 18.2, 13.5; 2, 144.9, 137.4, 128.4, 128.2, 128.1, 127.8, 126.7, 126.5, 82.7, 80.9, 80.7, 79.4, 71.23, 71.18, 57.3, 56.5, 53.1, 42.9, 25.1, 23.2, 23.13, 23.06 2, 128.2, 126.7, 126.5, 98.0, 83.4, 82.6, 82.0, 75.0, 71.4, 66.09, 66.07, 43.1, 35.5, 31.1, 24.9, 24.4, 23.5, 23.1, 23. 5, 141.9, 136.0, 128.9, 126.7, 83.9, 82.5, 80.9, 73.8, 71.3, 56.9, 52.9, 42.6, 30.9, 25.4, 23.2, 23.0, 22.9, 21.8, 20.9, 18.3, 13.5 Compound S3h was prepared from S2h and 4, 143.6, 132.3, 128.3, 128.1, 84.0, 82.3, 81.4, 73.6, 71.0, 56.8, 52.9, 42.7, 30.9, 24.9, 23.4, 23.2, 22.9, 21.8, 18.3, 13.5; DART MS m/z 447 (M + +1, 9.27); DART HRMS calcd for C 25 H 32 ClO 5 447.1938ClO 5 447. , found 447.1933. 3, 83.9, 82.4, 80.8, 73.7, 71.1, 56.7, 52.8, 42.9, 30.8, 25.0, 23.0, 22.9-22.3 (m) 3, 169.6, 169.4, 147.1, 140.1, 133.3, 129.0, 128.4, 128.3, 126.5, 126.0, 112.8, 110.5, 79.5, 72.9, 56.6, 52.92, 52.89, 40.9, 29.1, 28.9, 28.0, 23.1, 3.5; DART MS m/z 495 (M + +1, 100); DART HRMS calcd for C 28 H 31 O 6 S 495.1841, found 495.1847.…”

SelectFluor and Its Analogs Fluorination for Preparing Alkenyl Fluorides

“…For example, allenylmethylsilanes were employed SelectFluor and Its Analogs Fluorination for Preparing Alkenyl Fluorides, Scheme 1 Electrophilic addition of fluorine to alkenes using F-TEDA-BF 4 . The carbocation generated typically reacts with (weak) nucleophiles, unless it is sufficiently stable to allow elimination to prepare fluorinated dienes in good yields and excellent regioselectivity under mild basic conditions (Scheme 4b) [14]. This reaction was the first route to fluorinated dienes that did not require fluorinated starting materials.…”