Tertiary Amides as Fluoroalkyl Aldehyde Surrogates: Access to <i>meso</i>-Fluorinated Bis(heteroaryl)methanes

Tertiary, morpholine-derived, fluoroalkyl amides have been found to be efficient, readily accessible, bench-stable surrogates of fluoroalkyl aldehydes. This discovery is applied to the one-pot synthesis of a symmetrical and, more challengingly, unsymmetrical meso-fluoroalkylated bis­(heteroaryl)­methanes via a Schwartz’s reagent-mediated reductive activation. The usefulness of this approach for the introduction of a fluoromethylated carbon bridge was proven by implementation of the developed methodology in the synthesis of a fluorine-decorated bispyrromethane skeleton and an α-alkylated BODIPY core

Approach to Monobactams and Nocardicins via Diastereoselective Kinugasa Reaction

A Kinugasa reaction between copper­(I) acetylides and cyclic nitrones derived from chiral amino alcohols and glyoxylic acid is reported. The stereochemical preferences observed in this reaction are discussed. The alkyne molecule approaches the nitrone exclusively <i>anti</i> to the large substituent next to the nitrogen atom to provide the <i>cis</i>-substituted β-lactam ring preferentially. The six-membered oxazinone ring can be opened by reduction with lithium borohydride. Deprotection of the β-lactam nitrogen atom can be achieved by lithium in liquid ammonia reduction or by CAN oxidation, depending on the substituents attached to the four-membered azetidinone ring. The adducts obtained by the Kinugasa reaction provide an attractive entry to a variety of monocyclic β-lactam structures related to monobactams and nocardicins

Approach to Monobactams and Nocardicins via Diastereoselective Kinugasa Reaction

A Kinugasa reaction between copper­(I) acetylides and cyclic nitrones derived from chiral amino alcohols and glyoxylic acid is reported. The stereochemical preferences observed in this reaction are discussed. The alkyne molecule approaches the nitrone exclusively <i>anti</i> to the large substituent next to the nitrogen atom to provide the <i>cis</i>-substituted β-lactam ring preferentially. The six-membered oxazinone ring can be opened by reduction with lithium borohydride. Deprotection of the β-lactam nitrogen atom can be achieved by lithium in liquid ammonia reduction or by CAN oxidation, depending on the substituents attached to the four-membered azetidinone ring. The adducts obtained by the Kinugasa reaction provide an attractive entry to a variety of monocyclic β-lactam structures related to monobactams and nocardicins

Approach to Monobactams and Nocardicins via Diastereoselective Kinugasa Reaction

A Kinugasa reaction between copper­(I) acetylides and cyclic nitrones derived from chiral amino alcohols and glyoxylic acid is reported. The stereochemical preferences observed in this reaction are discussed. The alkyne molecule approaches the nitrone exclusively <i>anti</i> to the large substituent next to the nitrogen atom to provide the <i>cis</i>-substituted β-lactam ring preferentially. The six-membered oxazinone ring can be opened by reduction with lithium borohydride. Deprotection of the β-lactam nitrogen atom can be achieved by lithium in liquid ammonia reduction or by CAN oxidation, depending on the substituents attached to the four-membered azetidinone ring. The adducts obtained by the Kinugasa reaction provide an attractive entry to a variety of monocyclic β-lactam structures related to monobactams and nocardicins

Ferrier−Petasis Rearrangement of 4-(Vinyloxy)azetidin-2-ones: An Entry to Carbapenams and Carbacephams

Trimethylsilyl triflate promotes Ferrier−Petasis rearrangement of 4-(vinyloxy)-, 4-(propenyloxy)-, and 4-(isopropenyloxy)azetidin-2-ones to corresponding 4-(carbonylmethyl)azetidin-2-ones. The latter compounds may serve as attractive intermediates in the synthesis of carbapenem antibiotics. To illustrate the potential of this reaction, selected rearrangement products have been transformed into carbapenams

Ferrier−Petasis Rearrangement of 4-(Vinyloxy)azetidin-2-ones: An Entry to Carbapenams and Carbacephams

Trimethylsilyl triflate promotes Ferrier−Petasis rearrangement of 4-(vinyloxy)-, 4-(propenyloxy)-, and 4-(isopropenyloxy)azetidin-2-ones to corresponding 4-(carbonylmethyl)azetidin-2-ones. The latter compounds may serve as attractive intermediates in the synthesis of carbapenem antibiotics. To illustrate the potential of this reaction, selected rearrangement products have been transformed into carbapenams