Chromium carbonyl, cationic derivatives

The high stereoselectivity for the preparation of y-lactone derivatives is contributed to a conformation of the o-substituted benzaldehyde chromium complexes, in which a carbonyl oxygen of the benzaldehyde chromium complexes is oriented anti to the ort/zo-substituent due to a stereoelectronic effect, and samarium iodide attacks to the anti-oriented carbonyl from an opposite side to Cr(CO)3 fragment (Scheme 1). The generated benzyl cation 11 incorporates a... 

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