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1,3-Asymmetric induction in retro-[1,4]-brook rearrangements of propargyllithium compounds to propargylsilanes

✍ Scribed by Frank Sammtleben; Mathias Noltemeyer; Reinhard Brückner

Book ID: 104257124
Publisher: Elsevier Science
Year: 1997
Tongue: French
Weight: 245 KB
Volume: 38
Category: Article
ISSN: 0040-4039
DOI: 10.1016/s0040-4039(97)00762-4

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✦ Synopsis

The "y-siloxylated propargyl phenyl sulfides 3a-d, 5, and 6 were lithiated with lithium naphthalenide at -78°C in THF. They gave propargyllithium intermediates which rearranged within 10-30 min to the propargylsilanes 4a-d, 7, and 8, respectively. In these compounds the relative orientations of 7-C-O vs. newly formed C-Si bonds were determined by a crystal structure analysis of the dinitrobenzoate syn-10, inferred from NMR shift homologies or found by a Karplus analysis of pertinent J~i, values. The anti:syn selectivities of these retro-[l,4]-Brook rearrangements are probably kinetically controlled. They range from 81:19 anti:syn starting from sulfide 3a to 87:13 syn:anti starting from sulfide 3d.

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