Organic synthesis using haloboration reaction xv. A new synthesis of α,β-unsaturated esters by the highly chemoselective reaction of B-I-9-BBN-ethoxyethyne adduct with aldehydes
✍ Scribed by Yoshitaka Satoh; Takao Tayano; Shoji Hara; Akira Suzuki
- Publisher
- Elsevier Science
- Year
- 1989
- Tongue
- French
- Weight
- 208 KB
- Volume
- 30
- Category
- Article
- ISSN
- 0040-4039
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✦ Synopsis
A haloboration adduct, formed by the reaction of B-iodo-9-borabicyclo[3.3. llnonanes with ethoxyethyne reacts with aldehydes chemoselectively under very mild conditions.
The subsequent hydrolytic work-up affords--a&unsaturated esters in good yields.
The transformation of aldehydes to two carbon-homologated @-unsaturated esters is one of the most important reactions (eq.l), and the modified Wittig reaction involving phosponate carbanion is most frequently used.1 However, such reaction requires basic conditions and base sensitive substrates can not be applied.
Described herein is a new reaction of Et-iodo-9-borabicyclo[3.3.l]nonanes (B-I-9-BBN's)2 and ethoxyethyne