Detail of "7424-91-1"

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Cyclopropyl building blocks for organic synthesis, part 100

Cyclopropyl building blocks for organic synthesis, part 100. Advanced syntheses of cyclopropylideneacetates - versatile multifunctional building blocks for organic synthesis. Limbach, Michael; Dalai, Suryakanta; De Meijere, Armin (Institut fuer Organische und Biomolekulare Chemie, Georg-August-Universitaet Goettingen, Goettingen 37077, Germany).Chemicals with cas numbers 832142-14-0 and 7424-91-1 also play role. Advanced Synthesis & Catalysis, 346(7), 760-766 (English) 2004 Wiley-VCH Verlag GmbH & Co. KGaA. CODEN: ASCAF7. ISSN: 1615-4150. DOCUMENT TYPE: Journal CA Section: 25 (Benzene, Its Derivatives, and Condensed Benzenoid Compounds) A well reproducible and inexpensive prepn. of cyclopropylideneacetates was developed. The key intermediate 2-(1'-mesyloxycyclopropyl)acetic acid (8), produced either from Me phenylacetate (1) or Me 3,3-dimethoxypropionate (5-Me) and Et 3,3-diethoxypropionate (5-Et) in a sequence of Kulinkovich reductive cyclopropanation, mesylation and oxidative cleavage or cleavage and oxidn., resp., was either converted to the benzyl ester 11b, or chlorinated (brominated) via the in situ formed acid chloride. The a-chloro- 12a and a-bromo ester 12b were dehydromesylated by treatment with NEt3 to furnish Me 2-chloro-2-cyclopropylideneacetate (3-Me) and the 2-bromo analog 4-Me with an overall yield of 68% (65%, 68%) and 52% (49%, 51%), resp., starting from 1 (5-Me, 5-Et). The parent benzyl cyclopropylideneacetate 2-Bn was obtained by dehydromesylation of 11b with KOCMe3 in tert-Bu Me ether with an overall yield of 60% (57%, 9%) from 1 (5-Me, 5-Et). .