Synthesis of 1-Chloroalkynes from Alkynylsilanes Using Trichloroisocyanuric Acid as Chlorinating Agent

Vilhelmsen MieHøjer. Andersson AsbjørnSune. Nielsen MogensBrøndsted. Synthesis  2009,  1469 

<P>When revisiting the reaction conditions and the product composition of the previously reported chlorination reaction, we found that the reaction products are, in the case of unsubstituted and donor-substituted arylalkynes (R = H, OMe, t-Bu), not exclusively the reported chloroalkynes but to a large extent also chlorinated ketones.</P><P>Corrected products and yields under various conditions for the chlorination of p-RC₆H₄C≡CSiMe₃ using trichloro­isocyanuric acid (TCCA) and silver nitrate are provided here. These should replace Scheme  [²] and Table  [¹] in the original paper. We apologize for the mistake and for any inconvenience it may have caused.</P><P></P>

Scheme 2

<TD VALIGN="TOP"> R (starting material) </TD><TD VALIGN="TOP"> Scale^a </TD><TD VALIGN="TOP"> TCCA^b </TD><TD VALIGN="TOP"> AgNO₃^c </TD><TD VALIGN="TOP"> Conditions^d </TD><TD VALIGN="TOP"> Product yields (%) </TD><TD VALIGN="TOP"> CN (1) </TD><TD VALIGN="TOP"> 1.53 </TD><TD VALIGN="TOP"> 1.03 </TD><TD VALIGN="TOP"> 0.10 </TD><TD VALIGN="TOP"> 0 ˚C for 5 h </TD><TD VALIGN="TOP"> 2 (93) </TD><TD VALIGN="TOP"> CN (1) </TD><TD VALIGN="TOP"> 1.59 </TD><TD VALIGN="TOP"> 1.03 </TD><TD VALIGN="TOP"> 0.19 </TD><TD VALIGN="TOP"> H₂O (19 equiv); 0 ˚C for 30 min, then 40 ˚C for 24 h </TD><TD VALIGN="TOP"> 2 (84) </TD><TD VALIGN="TOP"> CN (1) </TD><TD VALIGN="TOP"> 1.54 </TD><TD VALIGN="TOP"> 1.07 </TD><TD VALIGN="TOP"> 0.20 </TD><TD VALIGN="TOP"> H₂O (20 equiv); 0 ˚C for 30 min, then µw for 5 min </TD><TD VALIGN="TOP"> 2 (98) </TD><TD VALIGN="TOP"> H (3a) </TD><TD VALIGN="TOP"> 1.82 </TD><TD VALIGN="TOP"> 1.00 </TD><TD VALIGN="TOP"> 0.10 </TD><TD VALIGN="TOP"> 0 ˚C for 5 h, then r.t. for 19 h </TD><TD VALIGN="TOP"> 3b (23) </TD><TD VALIGN="TOP"> H (3a) </TD><TD VALIGN="TOP"> 1.02 </TD><TD VALIGN="TOP"> 1.08 </TD><TD VALIGN="TOP"> 0.21 </TD><TD VALIGN="TOP"> 0 ˚C for 30 min, then reflux for 20 h </TD><TD VALIGN="TOP"> 3 (7); 3b (34); 3c (8) </TD><TD VALIGN="TOP"> H (3a) </TD><TD VALIGN="TOP"> 1.02 </TD><TD VALIGN="TOP"> 1.09 </TD><TD VALIGN="TOP"> 0.20 </TD><TD VALIGN="TOP"> 0 ˚C for 30 min, then µw for 5 min </TD><TD VALIGN="TOP"> 3 (<20); 3b (8); 3c (10) </TD><TD VALIGN="TOP"> OMe (4) </TD><TD VALIGN="TOP"> 1.54 </TD><TD VALIGN="TOP"> 1.00 </TD><TD VALIGN="TOP"> - </TD><TD VALIGN="TOP"> Bu₄NF (1 M soln in THF; 0.68 equiv); 0 ˚C for 70 min, then r.t. for 30 min </TD><TD VALIGN="TOP"> 5 (11); 6 (25) </TD><TD VALIGN="TOP"> OMe (4) </TD><TD VALIGN="TOP"> 1.59 </TD><TD VALIGN="TOP"> 1.07 </TD><TD VALIGN="TOP"> 0.09 </TD><TD VALIGN="TOP"> 0 ˚C for 30 min, then 40-50 ˚C for 72 h </TD><TD VALIGN="TOP"> 6 (31); 4c (27); 4d (21) </TD><TD VALIGN="TOP"> OMe (4) </TD><TD VALIGN="TOP"> 1.03 </TD><TD VALIGN="TOP"> 1.07 </TD><TD VALIGN="TOP"> 0.20 </TD><TD VALIGN="TOP"> 0 ˚C for 30 min, then reflux for 20 h </TD><TD VALIGN="TOP"> 6 (29); 4c (37) </TD><TD VALIGN="TOP"> OMe (4) </TD><TD VALIGN="TOP"> 1.03 </TD><TD VALIGN="TOP"> 1.08 </TD><TD VALIGN="TOP"> 0.19 </TD><TD VALIGN="TOP"> 0 ˚C for 30 min, then µw for 5 min </TD><TD VALIGN="TOP"> 6 (26); 4c (24) </TD><TD VALIGN="TOP"> NO₂ (8a) </TD><TD VALIGN="TOP"> 1.38 </TD><TD VALIGN="TOP"> 1.10 </TD><TD VALIGN="TOP"> 0.21 </TD><TD VALIGN="TOP"> H₂O (20 equiv); 0 ˚C for 30 min, then 40 ˚C for 24 h </TD><TD VALIGN="TOP"> 8 (50) </TD><TD VALIGN="TOP"> NO₂ (8a) </TD><TD VALIGN="TOP"> 1.40 </TD><TD VALIGN="TOP"> 1.12 </TD><TD VALIGN="TOP"> 0.21 </TD><TD VALIGN="TOP"> H₂O (20 equiv); 0 ˚C for 5 min, then µw for 5 min </TD><TD VALIGN="TOP"> 8 (42) </TD><TD VALIGN="TOP"> NO₂ (8a) </TD><TD VALIGN="TOP"> 1.00 </TD><TD VALIGN="TOP"> 1.12 </TD><TD VALIGN="TOP"> 0.20 </TD><TD VALIGN="TOP"> 0 ˚C for 30 min, then reflux for 20 h </TD><TD VALIGN="TOP"> 8 (76) </TD><TD VALIGN="TOP"> NO₂ (8a) </TD><TD VALIGN="TOP"> 1.00 </TD><TD VALIGN="TOP"> 1.10 </TD><TD VALIGN="TOP"> 0.20 </TD><TD VALIGN="TOP"> 0 ˚C for 30 min, then µw for 5 min </TD><TD VALIGN="TOP"> 8 (>99) </TD><TD VALIGN="TOP"> t-Bu (9a) </TD><TD VALIGN="TOP"> 1.08 </TD><TD VALIGN="TOP"> 1.13 </TD><TD VALIGN="TOP"> 0.23 </TD><TD VALIGN="TOP"> H₂O (20 equiv); 0 ˚C for 30 min, then 40 ˚C for 30 min </TD><TD VALIGN="TOP"> 9 (43); 9b (57) </TD><TD VALIGN="TOP"> t-Bu (9a) </TD><TD VALIGN="TOP"> 0.84 </TD><TD VALIGN="TOP"> 1.11 </TD><TD VALIGN="TOP"> 0.20 </TD><TD VALIGN="TOP"> H₂O (20 equiv); 0 ˚C for 5 min, then µw for 5 min </TD><TD VALIGN="TOP"> 9 (26); 9b (58) </TD><TD VALIGN="TOP"> t-Bu (9a) </TD><TD VALIGN="TOP"> 0.97 </TD><TD VALIGN="TOP"> 1.13 </TD><TD VALIGN="TOP"> 0.21 </TD><TD VALIGN="TOP"> 0 ˚C for 30 min, then reflux for 20 h </TD><TD VALIGN="TOP"> 9b (34); 9c (23) </TD><TD VALIGN="TOP"> t-Bu (9a) </TD><TD VALIGN="TOP"> 1.02 </TD><TD VALIGN="TOP"> 1.08 </TD><TD VALIGN="TOP"> 0.20 </TD><TD VALIGN="TOP"> 0 ˚C for 30 min, then µw for 5 min </TD><TD VALIGN="TOP"> 9b (19); 9c (<13) </TD><TD COLSPAN="20">

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</TD></TR><TR><TD VALIGN="TOP" COLSPAN="6"> ^a Amount of p-RC₆H₄CºCSiMe₃ in mmol.
^b Molar equivalents of TCCA relative to p-RC₆H₄CºCSiMe₃.
^c Molar equivalents of AgNO₃ relative to p-RC₆H₄CºCSiMe₃.
^d µw = microwave heating at 150 ˚C.
</TD>

Table 1 Corrected Products and Yields Obtained from Chlorination of p-RC₆H₄CºCSiMe₃