ABSTRACT
The reaction of silyldibromomethyllithium with aromatic imines provides alpha-amino acylsilanes via a bromo aziridine intermediate upon quenching the reaction with water. Alternatively, treatment of the bromo aziridine intermediate with various Grignard reagents or lithium aluminum hydride permits the nucleophilic displacement of the halogen to furnish substituted silyl aziridines.
ABSTRACT
A synthesis of alpha-keto acylsilanes, where 2-bromo-2H-azirine participates as a key intermediate, is reported. The reaction of silyldibromomethyllithium with aryl nitriles provides alpha-keto acylsilanes in good yields. Interestingly, silyldichloromethyllithium induces aza-1,3-Brook rearrangement of the silyl group in th reaction with nitriles. The rearrangement enables a three-component coupling reaction in a one-pot operation.
ABSTRACT
[reaction: see text] Treatment of formyl alpha,beta-enones with a TiCl(4)-R(4)NX combination induces an intramolecular aldol cyclization to furnish 2-acyl-3-halocyclohexanol with three controlled consecutive stereogenic centers. The reaction of bis-alpha,beta-enones with the combination provides cyclic diketones with high stereoselectivity via an intramolecular Michael addition reaction.
ABSTRACT
A convergent synthesis of a pyrimidine core has been achieved. Treatment of alpha,alpha-dibromo oxime ethers, which are easily derived from the corresponding esters, with a variety of Grignard reagents provides trisubstituted pyrimidines in good yields. This new method offers an easy access to functionalized pyrimidines.
