Ytterbium(III) Triflate-Catalyzed Amination of 1-Cyclopropylprop-2-yn-1-ols as an Expedient Route to Conjugated Enynes
摘要:
Ytterbium(III) triflate-catalyzed ring opening of substituted 1-cyclopropyl-2-propyn-1-ols with sulfonamides as an efficient synthetic route to conjugated enynes is described herein. The reaction was operationally straightforward and accomplished in moderate to good yields and recgioselective manner in all except one case under mild conditions.
Ytterbium(III) Triflate-Catalyzed Amination of 1-Cyclopropylprop-2-yn-1-ols as an Expedient Route to Conjugated Enynes
摘要:
Ytterbium(III) triflate-catalyzed ring opening of substituted 1-cyclopropyl-2-propyn-1-ols with sulfonamides as an efficient synthetic route to conjugated enynes is described herein. The reaction was operationally straightforward and accomplished in moderate to good yields and recgioselective manner in all except one case under mild conditions.
Ytterbium(III) Triflate-Catalyzed Amination of 1-Cyclopropylprop-2-yn-1-ols as an Expedient Route to Conjugated Enynes
作者:Weidong Rao、Xiaoxiang Zhang、Ella Min Ling Sze、Philip Wai Hong Chan
DOI:10.1021/jo8024626
日期:2009.2.20
Ytterbium(III) triflate-catalyzed ring opening of substituted 1-cyclopropyl-2-propyn-1-ols with sulfonamides as an efficient synthetic route to conjugated enynes is described herein. The reaction was operationally straightforward and accomplished in moderate to good yields and recgioselective manner in all except one case under mild conditions.
Highly Efficient Synthesis of Tri- and Tetrasubstituted Conjugated Enynes from Brønsted Acid Catalyzed Alkoxylation of 1-Cyclopropylprop-2-yn-1-ols with Alcohols
作者:Srinivasa Reddy Mothe、Philip Wai Hong Chan
DOI:10.1021/jo9008244
日期:2009.8.21
A highly efficient triflic acid catalyzed ring opening of a wide variety of 1-cyclopropyl-2-propyn-1-ols with alcohols as an efficient synthetic route to conjugated enynes is reported herein. The reaction was operationally straight forward and accomplished in good to excellent yields (44-100%,), high product turnovers (up to 10,000), and with complete regioselectivity under mild conditions with a low catalyst loading of 0.01 mol%. The mechanism is suggested to involve protonation of the alcohol substrate by the TfOH catalyst, followed by ionization of the starting material. This causes ring opening, of the cyclopropane moiety and trapping by the alcohol nucleophile to give the conjugated enyne product. The synthetic utility Of the present method was also exemplified by the efficient large-scale Conversion in grain quantities of one example studied in this work to the corresponding conjugated enyne product in excellent yield and turnover number.