High 1,3-Asymmetric Induction in Retro-[1,4]-Brook Rearrangements: Stereocontrolled Synthesis of Chiral Allyl Silanes
- 1 January 1994
- journal article
- letter
- Published by Georg Thieme Verlag KG in Synlett
- Vol. 1994 (12) , 1049-1053
- https://doi.org/10.1055/s-1994-23082
Abstract
The preponderantly cis- and preponderantly trans-configured allyl stannanes 15 and 17 which contain tBuPh2SiO and MePh2SiO substituents, respectively, were subjected to Sn/Li exchange reactions with nBuLi at -78°C. They gave allyl lithium intermediates which underwent retro-[1,4]-Brook rearrangements at this temperature within 20 - 40 min. They delivered the hydroxylated allyl silanes 22 and 18, respectively, with anti preference. The extent of stereocontrol depended almost only on the silyl group and much less on the double bond configuration. The highest selectivity was observed in the rearrangement of stannane trans-15 (tBuPh2Si group migrates, → anti-22; ds = 97:3), the lowest starting from stannane trans-17 (MePh2Si group migrates, → anti-18; ds = 67:33).Keywords
This publication has 0 references indexed in Scilit: