Enantioselective Copper-Catalyzed Arylation-Driven Semipinacol Rearrangement of Tertiary Allylic Alcohols with Diaryliodonium Salts
作者:Daniel H. Lukamto、Matthew J. Gaunt
DOI:10.1021/jacs.7b05340
日期:2017.7.12
A copper-catalyzed enantioselective arylative semipinacol rearrangement of allylic alcohols using diaryliodonium salts is reported. Chiral Cu(II)-bisoxazoline catalysts initiate an electrophilic alkene arylation, triggering a 1,2-alkyl migration to afford a range of nonracemic spirocyclic ketones with high yields, diastereo- and enantioselectivities.
Cracked under strain: Strained allylic cyclobutanols and cyclopropanols readily undergo a ring expansion described by the title rearrangement. This reaction is promoted by catalytic amounts of 1 and displays high tolerance with respect to the substrate scope. The corresponding β‐fluoro spiroketone products are isolated in high yields and with excellent stereoselectivities. EDG=electron‐donating group
the heavier halogens (bromine and iodine) second, the scope and limitations of the halogenative phase‐transfer methodology will be discussed and compared. An extension of the fluorination/semi‐pinacol reaction to the ring‐expansion of five‐membered allylic cyclopentanols will be also described, as well as some preliminary results on substrates prone to desymmetrization will be given. Finally, the present
Copper-Catalyzed Enantioselective Domino Arylation/Semipinacol Rearrangement of Allylic Alcohols with Diaryliodonium Salts
作者:Hua Wu、Qian Wang、Jieping Zhu
DOI:10.1002/chem.201703563
日期:2017.9.21
Selective arylation and shift: Copper-catalyzed enantioselective arylative semipinacol rearrangement of allylic alcohols with diaryliodonium salts afforded spirocycloalkanones in good to high yields with high diastereo- and enantioselectivities.
A catalytic asymmetric one-pot [3+2] cyclization/semipinacol rearrangement sequence: an efficient construction of a multi-substituted 3<i>H</i>-spiro[benzofuran-2,1′-cyclopentane] skeleton
facile and efficient method to form a chiral multi-substituted 3H-spiro[benzofuran-2,1′-cyclopentane] structural unit has been developed via a one-pot [3+2] cyclization/semipinacol rearrangement cascade. A catalysis system of Cu(II)/BOX has been used to efficiently construct a key stereogenic center via a cyclization between substituted benzoquinones and allylic alcohols affording the desired products