A convenient method for the preparation of 4- or 5-substituted 3-sulfonyl-δ-lactams via regioselectivereduction of N-alkyl-3-sulfonyl glutarimides is described. Formal synthesis of (±)-paroxetine and (±)-tacamonine is also reported.
One-pot facile conversion of Baylis–Hillman adduct into N-alkyl 3-(E)-alkylidene-5-substituted sulfonylpiperidine-2,6-dione. Formal synthesis of tacamonine
stepwise [3+3] strategy to N-alkyl 3-(E)-alkylidene-5-substituted sulfonylpiperidine-2,6-dione 1 used various N-alkyl α-substituted sulfonylacetamides 2 and α,β-unsaturated esters 3 as starting materials. α,β-Unsaturated esters 3 were generated by Baylis–Hillman reaction. A ring closure mechanism was proposed for the reactions. This method provides a convenient formal synthesis of tacamonine.
The efficient synthesis of indolo[2,3-alpha]quinolizin-4-ones 2 is described in two steps via formal [3 + 3] cycloaddition reaction of alpha-sulfonyl tryptaminylacetamide 4 with various alpha, beta-unsaturated esters 5 and the regioselective reduction of the resulting glutarimides 3 with sodium borohydride then sequent further dehydrated cyclization in the presence of boron trifluoride etherate. The useful building block is applied to synthesize deplancheine (1a) and yohimbane (1b). (C) 2004 Elsevier Ltd. All rights reserved.