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Cyclopropyl Building Blocks for Organic Synthesis, 36. Unprecedented Addition of Dialkoxycarbenes to Tetrasubstituted Alkenes: Bicyclopropylidene and 2‐Chlorocyclopropylideneacetate
Author(s) -
de Meijere Armin,
Kozhushkov Sergei I.,
Yufit Dmitry S.,
Boese Roland,
Haumann Thomas,
Pole David L.,
Sharma Pradeep K.,
Warkentin John
Publication year - 1996
Publication title -
liebigs annalen
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.825
H-Index - 155
eISSN - 1099-0690
pISSN - 0947-3440
DOI - 10.1002/jlac.199619960421
Subject(s) - chemistry , cyclopropane , intramolecular force , cycloaddition , heptane , nucleophile , nucleophilic addition , double bond , ring (chemistry) , stereochemistry , medicinal chemistry , organic chemistry , catalysis
The cycloaddition reactions of several dialkoxycarbenes generated in situ from the corresponding 2,2‐dialkoxy‐Δ 3 ‐1,3,4‐oxadiazolines of the type 3 with bicyclopropylidene 1 afford the dialkyl acetals of dispiro[2.0.2.1]heptane‐7‐one ( 4 ), whereas the analogous addition to methyl (1‐chloromethylene‐1‐carboxylate)cyclopropane 26 leads to the formation of a complex mixture of products. Those products can best be rationalized in terms of nucleophilic attack of the dialkoxycarbene on the strained CC double bond, to form a dipolar intermediate capable of a variety of intramolecular rearrangements. Several chemical transformations of the compounds of type 4 are reported.