Approach to synthesis of novel chiral 3-chloro-2(5H)-furanone and its application in asymmetric reactions

The synthetic method of the novel chiral synthon, 5-/-menthyloxy-3-chloro-2 -(5H)-furanone 5a and its application in asymmetric reactions were investig ated. 5a is easily obtained in highly optical purity, and acts as a stable acceptor of Michael addition with oxygen nucleophiles in tandem double Mich ael addition / internal nucleophilic substitution to offer the spiro-cyclop ropane derivative containing four stereogenic centers 8, which it is diffic ult to obtain by routine methods. The synthetic methods for 5a and 8 are re ported in detail and the new compounds are identified on the basis of their analytical data and spectroscopic data, such as UV, IR, H-1 NMR, C-13 NMR, MS and elementary analysis. The absolute configuration of the interesting spiro-cyclopropanes, spiro [1-chloro-4-(l-menthyloxy)-5-oxo-6-oxa-biscyclo[ 3.1.0]hexane-2,3'-(4'-/-menthyloxy-5'-l-menthyloxy-butyrolactone)] 8 was es tablished by X-ray crystallography. This result can provide important synth etic strategy in synthesis of some complex molecules containing spiro-cyclo propane skeleton with multiple chiral centers.