Modified Pictet–Spengler reaction. A highly diastereoselective approach to 1,2,3-trisubstituted-1,2,3,4-tetrahydro-β-carbolines using perhydro-1,3-heterocycles
摘要:
A flexible variant of the Pictet-Spengler reaction employing oxazinanes as synthetic equivalents of several carbonyl compounds has been developed. Using acid catalyzed one pot condensation of perhydro-1,3-heterocycles various 1,3-disubstituted and 1,2,3-trisubstituted-1,2,3,4-tetrahydro-beta -carbolines (THBCs) have been synthesized diastereoselectively. (C) 2001 Elsevier Science Ltd. All rights reserved.
Pictet–Spengler reaction: is carbonyl the best choice? A highly diastereoselective alternative approach to trans-1,3-disubstituted tetrahydro-β-carbolines
摘要:
Unprecedented 1,2,3-trisubstituted tetrahydro-beta-carbolines (THBCs) have been synthesized via a short and highly diastereoselective synthetic route. The key step of the sequence is a flexible variant of the Pictet-Spengler reaction employing synthetic equivalents of several non-available carbonyl compounds. Using one such synthon, the resultant THBC could be further ring-closed to a tetracyclic indole alkaloidal skeleton. (C) 2000 Elsevier Science Ltd. All rights reserved.
A synthetic entry into fused pyran derivatives through carbon transfer reactions of 1,3-oxazinanes and oxazolidines with carbon nucleophiles
作者:Kamaljit Singh、Jasbir Singh、Harjit Singh
DOI:10.1016/0040-4020(96)00879-4
日期:1996.11
of various 2 substituted 1,3-oxazinanes 3 and 1,3-oxazolidines 4 with cyclic carbonnucleophiles viz. 5,5-dimethyl-1,3-cyclohexanedione and 1,3-cyclohexanedione furnish xanthene derivatives, whereas a Knoevenagel reaction proceeds with acyclic nucleophiles. In case of 4b and 4c, a unique synthesis of functionalised α-tetralones has emerged. Reactions of mixtures of cyclic and acyclic carbon nucleophiles