Synthesis of pyroglutamic acid derivatives via double Michael addition reactions of alkynones.

摘要

I. Synthesis of pyroglutamic acid derivatives via double Michael reactionsudof alkynonesudPyroglutamic acids and their derivatives are common structural units of widespreadudchemical significance and they have been heavily utilised as building blocks forudasymmetric synthesis.udA new method for the synthesis of highly functionalised pyroglutamic acidudderivatives, which consists in a Double Michael addition route that utilises amidetetheredudcarbon diacids and aromatic alkynones as substrates, is here described. Theudreaction proceeds with good levels of trans-diastereoselectivity, provided thatudsubstoichiometric quantities of Mg(OTf)2 or Ni(acac)2 are employed. II. Michael additions combined with Friedel-Crafts cyclisationsudA domino Michael/Friedel-Crafts alkyation of aryl ethers with propargyl ketones wasuddeveloped as a continuation of our double Michael additions. The reaction, hereuddescribed, proceeds in good yield over two steps, when the aryl ethers and alkynonesudare treated with substoichiometric quantities of Yb(OTf)3 and heated to 100 oC in audmicrowave oven.