Complete Stereoretention in the Rhodium-Catalyzed 1,2-Addition of Chiral Secondary and Tertiary Alkyl Potassium Trifluoroborate Salts to Aldehydes
作者:Abel Ros、Varinder K. Aggarwal
DOI:10.1002/anie.200901900
日期:——
Take your new partner by the hand: Chiralsecondary and tertiaryalkyltrifluoroboratesalts undergo rhodium‐catalyzed 1,2‐addition to aldehydes with completestereoretention (handedness) in all cases, enabling the creation of quaternary stereogenic centers with essentially perfect enantioselectivity (see scheme; cod=cycloocta‐1,5‐diene).
The KHMDS-catalyzed tertiary alkylation of aldehydes, ketones or imines using tertiary benzylic organoboronates is reported. This protocol permitted the use of tertiary benzylic alkylboronates as t...
Rhodium-Catalyzed Allylic Substitution with an Acyl Anion Equivalent: Stereospecific Construction of Acyclic Quaternary Carbon Stereogenic Centers
作者:P. Andrew Evans、Samuel Oliver、Jungha Chae
DOI:10.1021/ja306602g
日期:2012.11.28
A highly regio- and stereospecific rhodium-catalyzed allylic alkylation of tertiary allylic alcohol derivatives with a cyanohydrin pronucleophile is described. This direct and operationally simple protocol provides a fundamentally novel approach toward the synthesis of α-quaternary substituted ketones and circumvents many of the inherent problems associated with conventional enolate alkylation reactions