Addition of Cl2C:  to (−)-O-Menthyl
Acrylate under Sonication−Phase-Transfer
Catalysis. Efficient Synthesis of (+)- and
(−)-(2-Chlorocyclopropyl)methanol

Masuno, Makoto N.; Young, Douglas M.; Hoepker, Alexander C.; Skepper, Colin K.; Molinski, Tadeusz F.

doi:10.1021/jo0480186.s001

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Addition of Cl₂C: to (−)-O-Menthyl Acrylate under Sonication−Phase-Transfer Catalysis. Efficient Synthesis of (+)- and (−)-(2-Chlorocyclopropyl)methanol

2005-05-13T00:00:00Z (GMT) by Makoto N. Masuno Douglas M. Young Alexander C. Hoepker Colin K. Skepper Tadeusz F. Molinski

Dichlorocyclopropanation of (−)-O-menthyl acrylate under conditions of phase-transfer catalysis (CHCl₃, KOH, tetramethylammonium bromide), with sonication, gives excellent yields (85−94%) of the corresponding dichlorocyclopropanecarboxylate ester compared to thermal conditions (90 °C, 56%). No diastereoselectivity was observed, but one isomer was isolated pure by fractional crystallization. The measured kinetic isotope effect (initial rate (CHCl₃)/rate (CDCl₃) ∼1.7) suggests deprotonation of CHCl₃ as the rate-limiting step.

Keyword(s)

KOH isomer bromide diastereoselectivity Menthyl Acrylate Catalysi crystallization Dichlorocyclopropanation Efficient Synthesis Sonication Chlorocyclopropyl deprotonation tetramethylammonium catalysi menthyl acrylate CHCl 3 isotope effect yield sonication dichlorocyclopropanecarboxylate ester CDCl 3

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