We have designed a new class of MII-catalysts, namely molybdenum and tungsten (II) complexes of the type PhCH2(Et)3N+[M(CO)4C1Br2]- and M(CO)5(OTf)2 (M = Mo or W), which induce intramolecular cyclization of olefinic aldehydes to afford products with a cis-configuration at the newly formed chiral centres in some cases. These catalysts can be tuned to drive the reaction either toward the end or Prins-type product (32 or 89). The latter reaction occurs via an anti addition of the carbonyl carbon and OH across the C=C bond, as evidenced by isotopic labeling. A chair-like transition state with an axial carbonyl oxygen is proposed to rationalise the stereoselectivities observed.
| Identifer | oai:union.ndltd.org:bl.uk/oai:ethos.bl.uk:696261 |
| Date | January 1997 |
| Creators | Ahmed, Ghafoor |
| Publisher | University of Leicester |
| Source Sets | Ethos UK |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
| Source | http://hdl.handle.net/2381/29970 |
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