DMAP-catalyzed diastereoselective [3 + 3] spiroannulations of isatin-derived Morita-Baylis-Hillman car-bonates with indoline-2-thiones were achieved. A series of bisindole-annulated thiopyran frameworks were synthesized in good yields with good diastereoselectivities. The strategy developed in this paper offered a novel way for the synthesis of valuable indole-annulated sulfur heterocycle derivatives which might be beneficial in organic synthesis and medicinal chemistry. (c) 2022 Elsevier Ltd. All rights reserved.
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