One-Pot in Situ Formation and Reaction of Trimethyl(trichloromethyl)silane: Application to the Synthesis of 2,2,2-Trichloromethylcarbinols
摘要:
2,2,2-Trichloromethylcarbinols are 1 are valuable synthetic intermediates with a multitude of uses. A scalable procedure for the synthesis of TMS-protected-2,2,2-trichloromethylcarbinols and 2,2,2-trichloromethylcarbinols 1 was developed that employs the in situ generation and reaction of trimethyl(trichloromethyl)silane (CCl3-TMS). The procedure avoids the exposure of the carbonyl compounds to the strongly basic conditions typically used for this transformation and also avoids isolation of the difficult-to-handle CCl3-TMS. This procedure was applied to diastereoselective trichloromethyl additions to 2-substituted 4-piperidinones and to reactions with a variety of structurally diverse aldehydes and ketones.
Reactions of coordinated geminal dichromium reagents with aldehydes: stereoselective formation of (Z)-2-chloroalk-2-en-1-ols
作者:Kazuhiko Takai、Ryo Kokumai、Takahumi Nobunaka
DOI:10.1039/b102387j
日期:——
Treatment of a carbonate ester of 2,2,2-trichloroethanol
derivative with CrCl2–DMF in THF gives a
β-carbonate-coordinated geminal dichromium species, which adds to an
aldehyde and eliminates an acyloxychromium group to afford a
(Z)-2-chloroalk-2-en-1-ol stereoselectively.