Asymmetric Allyl- and Crotylboration with the Robust, Versatile, and Recyclable 10-TMS-9-borabicyclo[3.3.2]decanes
- 10 May 2005
- journal article
- research article
- Published by American Chemical Society (ACS) in Journal of the American Chemical Society
- Vol. 127 (22), 8044-8049
- https://doi.org/10.1021/ja043612i
Abstract
The remarkable versatility and selectivity of the 10-(trimethylsilyl)-9-borabicyclo[3.3.2]decanes (10-TMS-9-BBDs) in the allyl- and crotylboration of representative aldehydes are reported. The new reagents are prepared through air-stable crystalline pseudoephedrine borinic ester complexes of the 10-TMS-9-BBDs (4), which are available in 63% overall yield from B-MeO-9-BBN through a simple two-step procedure. These complexes 4 are directly converted to the corresponding B-allyl-10-TMS-9-BBDs (1) with allylmagnesium bromide, which either can be isolated (98%) or used in situ for the allylations. The remarkable enantioselectivity (96 to ≥99% ee) of these reagents in the rapid (B-crotyl-10-TMS-9-BBDs (10) from optically pure enantiomers of B-MeO-10-TMS-9-BBD (3). These reagents 10 also add rapidly (<3 h) and efficiently to representative aldehydes at −78 °C, providing ready access to all four of the possible stereoisomers of the β-methyl homoallylic alcohols 12−15 (69−92%) in high dr (≥98:2) and ee (94−99%).Keywords
This publication has 59 references indexed in Scilit:
- Lewis Acid Catalyzed Allylboration: Discovery, Optimization, and Application to the Formation of Stereogenic Quaternary Carbon CentersThe Journal of Organic Chemistry, 2004
- Bidirectional Asymmetric Allylboration. A Convenient Asymmetric Synthesis of C2-Symmetric 3-Methylenepentane-1,5-diols and Rapid Access to C2-Symmetric SpiroketalsThe Journal of Organic Chemistry, 1999
- Theoretical Study of the Effects of Structure and Substituents on Reactivity in AllylborationThe Journal of Organic Chemistry, 1998
- Selective reactions using allylic metalsChemical Reviews, 1993
- Chiral synthesis via organoboranes. 35. Simple procedures for the efficient recycling of the terpenyl chiral auxiliaries and convenient isolation of the homoallylic alcohols in asymmetric allyl- and crotylboration of aldehydesThe Journal of Organic Chemistry, 1992
- A highly diastereoselective addition of [E]- and [Z]-crotyldiisopinocampheylboranes to .alpha.-substituted aldehydesThe Journal of Organic Chemistry, 1987
- B-Allyldiisocaranylborane: a new, remarkable enantioselective allylborating agent for prochiral aldehydes. Synthesis of homoallylic alcohols approaching 100% enantiomeric puritiesThe Journal of Organic Chemistry, 1984
- Stereoselektive Synthese von Alkoholen, VI1) Asymmetrische Synthesen von 4‐Penten‐2‐ol über Allylboronsäureester chiraler GlycoleEuropean Journal of Inorganic Chemistry, 1981
- Stereoselektive Synthese von Alkoholen, VII1) Optisch aktive Homoallylalkohole durch Addition chiraler Boronsäureester an AldehydeEuropean Journal of Inorganic Chemistry, 1981
- Enantioselective Synthesis of Homoallyl Alcohols via Chiral Allylboronic EstersAngewandte Chemie-International Edition, 1978