作者:Xuan B. Nguyen、Yuji Nakano、Nisharnthi M. Duggan、Lydia Scott、Martin Breugst、David W. Lupton
DOI:10.1002/anie.201905475
日期:2019.8.12
Direct polarity inversion of conjugate acceptors provides a valuable entry to homoenolates. N‐heterocyclic carbene (NHC) catalyzed reactions, in which β‐unsubstituted conjugate acceptors undergo homoenolate formation and C−C bond formation twice, have been developed. Specifically, the all‐carbon (5+1) annulations give a range of mono‐ and bicyclic cyclohexanones (31 examples). In the first family of
Regioselective Radical Bromoallylation of Allenes Leading to 2-Bromo-Substituted 1,5-Dienes
作者:Takashi Kippo、Takahide Fukuyama、Ilhyong Ryu
DOI:10.1021/ol201395p
日期:2011.8.5
regioselective radical bromoallylation of allenes proceeded efficiently in the presence of AIBN as a radical initiator to give 2-bromo-substituted 1,5-dienes in excellent yields. The addition of a bromine radical took place regioselectively onto the central carbon of allenes generating a stable allyl radical, which underwent addition/β-fragmentation reactions with allylbromides. The products could be
Palladium-catalyzed reaction of CH2C(R)COOMe (R=H or CH2OH) with PhI in the presence of NEt3 under O2 induces the oxidative dealkylation of NEt3, affording either methyl 3-diethylaminopropionate (3) or methyl (Z)-2-benzyl-3-(N,N′-diethylamino)propenate (6), in case of R=H or R=CH2OH, respectively.
which otherwise are essentially reluctant towards F‐nucleoplilic addition, now readily participate in this fluoroallylation reaction. Furthermore, this strategy provides an elegant example for the generation, as well as functionalization, of α‐CF3‐substituted benzylic radical intermediates using cheap and readily available starting materials.
We describe Cu-catalyzed intermolecular alkynylation and allylation of unactivated C(sp3)–H bonds with singly occupied molecular orbital-philes (SOMO-philes) via hydrogen atom transfer (HAT). Employing N-fluoro-sulfonamide as a HAT reagent, a set of substituted alkene and alkyne compounds were synthesized in high yields with good regioselectivity and functional-group compatibility. Late-stage functionalization