Nickel-Catalyzed α-Benzylation of Arylacetonitriles <i>via</i>
CO Activation
作者:Jing Xiao、Jia Yang、Tieqiao Chen、Li-Biao Han
DOI:10.1002/adsc.201500822
日期:2016.3.3
Efficient Ni‐catalyzeddirect cross‐couplings of benzylic alcohol derivatives with arylacetonitriles via CO activation are described. Various α‐benzylated arylacetonitriles including those with functional groups can be prepared undermild reaction conditions.
Abstract (Pivaloyloxymethyl)zincchloride, obtained by an iodine–magnesium exchange and subsequent transmetalation, shows a much higher reactivity in Negishi cross-couplings than the corresponding zinc organometallic, prepared by direct zinc insertion. Furthermore, a substituted derivative of (pivaloyloxymethyl)zincchloride is prepared starting from pivaloyloxymethyl sulfoxide using TMPZnCl·LiCl (TMP
Photochemistry of Substituted Benzyl Acetates and Benzyl Pivalates: A Reinvestigation of Substituent Effects
作者:J. W. Hilborn、E. MacKnight、J. A. Pincock、P. J. Wedge
DOI:10.1021/ja00087a020
日期:1994.4
The photosolvolysis reactions, in methanol, of six substituted benzyl acetates (7a-f) and benzyl pivalates (8a-f) were studied. Five major benzylic products were formed from two critical intermediates. The ethers (9) were formed from the ion pair, 15, and all of the other products (10-14) were formed from the radical pair, 16. Quenching studies showed that only excited singlet state reactivity was important. The product yields were found to be highly substituent dependent. For instance, for the acetate esters, the yield of ether (9) varied from 2% for X = 4-OCH3 to 32% for X = 3-OCH3. Most of the differences in the yields could be attributed to ground state processes that occur after bond cleavage. The important competition is between electron transfer, converting the radical pair to the ion pair, and decarboxylation of RCO(2)(.). The rates of electron transfer are shown to fit Marcus theory in both the normal and inverted regions. Direct heterolytic cleavage to form the ion pair is of minimal importance.
Hilborn J. W., MacKnight E., Pincock J. A., Wedge P. J., J. Amer. Chem. Soc, 116 (1994) N 8, S 3337- 3346
作者:Hilborn J. W., MacKnight E., Pincock J. A., Wedge P. J.
DOI:——
日期:——
Pincock J.A., Wedge P.J., J. Org. Chem., 59 (1994) N 19, 5587-5595