4 A molecular sieves catalyze the mild conversion of activated secondary alcohols into the corresponding carbonyl compounds with t-butyl hydroperoxide (TBHP).
Chemoselective addition of in situ prepared lithium alkynyl borates to aldehydes: a practical and transition metal free approach toward the synthesis of propargylic alcohols
A convenient synthesis of functionalized propargylic alcohols arising from the 1,2-addition of lithium alkynyl-trimethyl borate onto aldehydes under transition metal free mild conditions is reported. The reaction tolerates a wide range of functional groups, is highly chemoselective and the propargylic alcohols are isolated in good to excellent yields.
A Pd(II)-catalyzed [3,3]-sigmatropicrearrangement is used to transfer chirality from an enantio-enriched alk-3-ene-1,2-diol to a C 2 -symmetrical alk-2-ene-1,4-diol which, in turn, can be converted into a precursor of (-)-methylenolactocin through an additional [3,3]-sigmatropicrearrangement (either Johnson orthoester or Ireland-Claisen rearrangement).
Broadly Applicable Ion Pair-Assisted Nucleophilic Substitution of sp<sup>3</sup>-Carbon Electrophiles with Alkynyltrifluoroborates
作者:Shiwen Liu、Cláudio F. Tormena、Gerald B. Hammond、Bo Xu
DOI:10.1021/acs.orglett.2c02507
日期:2022.9.2
smoothly with a wide range of sp3-carbon electrophiles, including propargyl methanesulfonates and unactivated alkyl triflates, to give Sonogashira-type products, via a novel ion pair-assisted nucleophilicsubstitution mechanism. An ion pair–organic complex, investigated using computational chemistry and in situ NMR experiments, may play a crucial role in this reaction.