Aspects of some alkylation reactions

Friedel-Crafts reactions of the (-)-8-phenylmenthyl and (+ )-trans-2-(acumyl)\ncycJohexyl aryl hydroxy acetates catalysed by trimethylsilyl triflate (TMSOTf)\nand equivalents in the presence of electron rich heterocycles gave the expected\ndiarylacetates in high de 88%, via a planar cation.\nThe interaction of trifluoromethanesulfonic (triflic) acid (TfOH) with either bistrimethylsilyl\n-acetamide (BSA) or -urea (BSU) can be used to generate\nstoichiometric amounts of trimethylsilyl triflate (TMSOTf) "in situ" , the system can\nbe used efficiently to remove triflic acid from TMSOTf and to generate catalytic\namounts of TMSOTf from TfOH for use in a range of trimethylsilyl triflate\n(TMSOTf) catalysed reactions.\nSimilarly the interaction of fluorosulfonic acid (FSA) with either bis-trimethylsilyl\n-acetamide (BSA) or -urea (BSU) can be used to generate catalytic amounts of\ntrimethylsilylfluorosulfonate (TMSOFs) "in situ" for use in a wide range of reactions\nas an alternative to trimethylsilyltriflate (TMSOTf)\nScandium(III) trifluoromethanesulfonate and copper(II) trifluoromethanesulfonate\ncan be used to catalyse aromatic alkylation with arylhydroxyacetates. Scandium(III)\ntrifluoromethanesulfonate also proved to be a recyclable catalyst for these reactions.\nA number of Pictet-Spengler cyclisation reactions were also catalysed by\nScandium(III) trifluoromethanesulfonate and copper(II) trifluoromethanesulfonate.\nMannich reactions of a number of caJix[4jresorcinarene derivatives with (R)-(+)-amethylbenzylamine\nunder alkaline conditions lead to the formation of single\ndiastereomeric tetrakis(l,3-dihydrobenzoxazine) derivatives in high yields; the\nreactions using the (S)-(-)-a-methylbenzylamine afford the enantiomers. The\nproducts react with protic acids to afford equilibrium mixtures of diastereomers.