Facile access to diverse all-carbon quaternary center containing spirobicycles by exploring a tandem Castro-Stephens coupling/acyloxy shift/cyclization/semipinacol rearrangement sequence.

Efficient combination of two or more reactions into a practically useful purification free sequence is of great significance for the achievement of structural complexity and diversity, and an important approach for the development of new synthetic strategies that are industrially step-economic and environmentally friendly. In this work, a facile and efficient method for the construction of highly functionalized spirocyclo[4.5]decane derivatives containing a synthetically challenging quaternary carbon center has been successfully developed through the realization of a tandem Castro-Stephens coupling/1,3-acyloxy shift/cyclization/semipinacol rearrangement sequence.

A catalytic asymmetric one-pot [3+2] cyclization/semipinacol rearrangement sequence: an efficient construction of a multi-substituted 3H-spiro[benzofuran-2,1'-cyclopentane] skeleton.

A facile and efficient method to form a chiral multi-substituted 3H-spiro[benzofuran-2,1'-cyclopentane] structural unit has been developed via a one-pot [3+2] cyclization/semipinacol rearrangement cascade. A catalysis system of Cu(ii)/BOX has been used to efficiently construct a key stereogenic center via a cyclization between substituted benzoquinones and allylic alcohols affording the desired products in good yields and with excellent enantioselectivities and diastereoselectivities (21 examples; up to 67% yields; up to 92% ee and up to >20 : 1 dr). This method provides an alternative strategy for the synthesis of the corresponding bioactive molecules containing spiro[benzofurancyclopentane] skeleton units.

Improved synthesis of 8-oxabicyclo[3.2.1]octanes via tandem C-H oxidation/oxa-[3,3] Cope rearrangement/aldol cyclization.

A tandem C-H oxidation/oxa-[3,3] Cope rearrangement/aldol reaction of allylic silylethers promoted by TBF(tempo oxoammonium tetrafluoroborate)/ZnBr has been successfully developed allowing the efficient construction of 8-oxabicyclo[3.2.1]octanes and their analogs with a wide substrate scope.