An Easy Access to Spiroisoxazoline [5,3<sup>1</sup>] Flavan-4<sup>1</sup>-one Through 1,3-Dipolar Cycloaddition Reaction of Nitrile Oxide to Unusual Dipolarophiles
Abstract Synthesis of a series of novel spiro[3,4-diaryl-4,5-dihydroisoxazole-5,31-flavan-41-one] has been accomplished in good yields by the regioselective 1,3-dipolar cycloaddition reaction of nitrile oxide to 3-arylmethylidene flavan-4-ones.
Spiropyrazolines have been synthesized by 1,3-dipolar cycloaddition of an 2-arylidene-1-tetralone, 3-arylidene-chromanones, -1-thiochromanones, and -flavanones with diazomethane. The relative configuration and stereochemistry of the products have been determined by means of one-dimensional difference N.O.E. measurements. It is shown that ring-closure reaction is regioselective, yielding stereohomogeneous
FLAVINDOGENIDES AS 2π COMPONENT IN 1,3-DIPOLAR CYCLOADDITION REACTION—AN EFFICIENT SYNTHESIS OF NEW CLASS OF DISPIROHETEROCYCLES
作者:S. Manikandan、R. Raghunathan
DOI:10.1081/scc-120014969
日期:2002.1
ABSTRACT The cycloadditionreaction of non-stabilised azomethine ylides towards (E) 3-arylidene flavan-4-ones or flavindogenides as new dipolarophile have been investigated. High degree of regio and stereoselectivity has been observed in the synthesis of unique class of densely functionalised dispiroheterocyclic compounds bearing flavan-4-one frameworks.
Mallik, Uttam K; Saha, Murari M; Mallik, Asok K, Indian Journal of Chemistry - Section B Organic and Medicinal Chemistry, 1992, vol. 31, # 11, p. 753 - 758