Nucleophilic phosphine catalysis is a practical and powerful synthetic tool for the synthesis of various heterocyclic compounds with the advantages of environmental-friendly, metal-free, and mild reaction conditions. The present report...

Herein we describe the first organocatalytic asymmetric C(sp2)−H allylation of racemic trisubstituted allenoates with Morita–Baylis–Hillman (MBH) carbonates to access axially chiral tetrasubstituted allenoates. Various trisubstituted allenoates and MBH carbonates were well tolerated under mild reaction conditions, providing novel chiral tetrasubstituted allenoates with adjacent axial chirality and tertiary carbon stereocenters in high yields with good to excellent diastereoselectivities and enantioselectivities.

A Lewis-base-catalyzed enantioselective [3 + 3] annulation reaction of Morita−Baylis−Hillman (MBH) carbonates with α-arylidene pyrazolinones is described, affording the pyrazolone-fused spirocyclohexenes bearing an all-carbon quaternary stereocenter in high yields with good to excellent diastereoselectivities and excellent enantioselectivities.

A palladium‐catalyzed [4+2] cycloaddition of hydroxy‐tethered allyl carbonates with five types of electron‐deficient alkenes has been achieved, in which a type of new hydroxy‐tethered allyl carbonates acted as valuable precursors for the formation of 1,4‐C,O‐dipole allylpalladium intermediates. The reaction proceeded efficiently under mild reaction conditions to provide the corresponding tetrahydropyran derivatives in moderate to high yields with excellent diastereoselectivities.

A phosphine-catalyzed [4 + 2] cycloaddition of cyclic α-substituted allenoates with sulfamate-derived cyclic imines has been reported. Using dibenzylphenylphosphine as the nucleophilic catalyst, the reaction worked efficiently to yield various fused multicyclic heterocyclic compounds in high yields with excellent diastereoselectivities. It undergoes a new reaction mode involving γ'-carbon of α-substituted allenoate.