Ring-Opening of Epoxides by Pendant Silanols

We present a new ring-opening reaction of epoxides by pendant silanols, catalyzed by either Ph3C+BF4– or BINOL-phosphoric acid. In all cases examined, the reaction is perfectly regioselective and diastereoselective. Silanol epoxides derived from trans-allylic alcohols, cis-allylic alcohols, trans-homoallylic alcohols, and cis-homoallylic alcohols were all compatible and gave products from either endo- or exo-ring opening. With silanol epoxides derived from 4-alkenyl silanols, an unusual rearrangement to tetrahydrofuran products was observed, which is likely the result of tandem nucleophilic attacks. The utility of this methodology was demonstrated in a short preparation of protected D-arabitol.

A rearrangement of saccharin-derived cyclic ketimines with 3-chlorooxindoles leading to spiro-1,3-benzothiazine oxindoles

An unusual rearrangement of saccharin-derived cyclic ketimines (SDCIs) and 3-chlorooxindoles has been developed to provide a series of spiro-1,3-benzothiazine oxindoles. The reaction features simple manipulation, short reaction time, mild reaction...

Unusual Rearrangement-Remercuration Reactions of Allylic Silanols

We present the first examples of rearrangement reactions of allylic silanol substrates into linear ketone and 5-membered cyclic silanediol organomercurial products. Both reactions are mediated by Hg(OTf)2 but differ in...

Unusual Rearrangement of Modified PNP Ligand based Ru Complexes Relevant to Alcohol Dehydrogenation Catalysis

We report the synthesis of ‘hangman-type’ PNP pincer ligands and their associated Ru complexes. Upon deprotonation, the complexes undergo sp²-sp³ C-C bond cleavage and subsequent C-C formation processes to form a new, one carbon unit longer backbone motif. Unlike the starting geometry, the products are completely inactive in alcohol dehydrogenation catalysis. DFT and mechanistic studies suggest an intramolecular isomerization process via a spyrocycle cyclopropane intermediate, dependent upon arm pyridine coordination and ligand sterics.

Unusual Rearrangement of Modified PNP Ligand based Ru Complexes Relevant to Alcohol Dehydrogenation Catalysis

We report the synthesis of ‘hangman-type’ PNP pincer ligands and their associated Ru complexes. Upon deprotonation, the complexes undergo sp²-sp³ C-C bond cleavage and subsequent C-C formation processes to form a new, one carbon unit longer backbone motif. Unlike the starting geometry, the products are completely inactive in alcohol dehydrogenation catalysis. DFT and mechanistic studies suggest an intramolecular isomerization process via a spyrocycle cyclopropane intermediate, dependent upon arm pyridine coordination and ligand sterics.

Unusual rearrangement of modified PNP ligand based Ru complexes relevant to alcohol dehydrogenation catalysis

Hangman PNP pincer Ru complexes undergo an unusual sp2–sp3 C–C bond cleavage and formation via a spyrocyclopropane transition state.

Copper(ii) self-assembled clusters of bis((pyridin-2-yl)-1,2,4-triazol-3-yl)alkanes. Unusual rearrangement of ligands under reaction conditions

Structure and magnetic data of new Cu(ii) complexes on the bispyridyltriazolylalkanes basis are described.

Unusual rearrangement of imidazo[1,5-a]imidazoles and imidazo[1,2-b]pyrazoles into imidazo[1,5-a]pyrimidines and pyrazolo[1,5-a]pyrimidines

A multicomponent reaction giving easy and cheap access to a variety of bicyclic 5,5-fused hetero-rings has been developed.