A general, efficient, convenient synthesis of chiral bis(terpenyl)haloborane reagents, valuable for asymmetric synthesis via organoboranes
โ Scribed by Ulhas P. Dhokte; Raman Soundararajan; P.Veeraraghavan Ramachandran; Herbert C. Brown
- Publisher
- Elsevier Science
- Year
- 1996
- Tongue
- French
- Weight
- 214 KB
- Volume
- 37
- Category
- Article
- ISSN
- 0040-4039
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๐ SIMILAR VOLUMES
The asymmetric crotylboration of representative aldehydes, RCHO (R = Me, Et-), with B-[Z and El-crotylbis@isocaranyl)boranes (4 and 5) proceeds with remarkably high enantioselectivity (>94-98% ee) and diastereoselectivity (>99% de) at -78 Oc in ethyl ether.
Preparahon of B-isoprenyldialkylboranes is achieved by adopting the Brandsma modification of the Schlosser procedure, namely metallation of isoprene with potassium 2,2,5,5tetramethylpiperidide followed by sequential treatment with B-methoxydialkylborane and boron trifluoride-etherate. These reagent