Anthony Dew pleaded guilty in the Superior Court to multiple counts of trafficking of a person for sexual servitude, in violation of G. L. c. 265, § 50 ( a ) ; assault and battery with a dangerous weapon, in violation of G. L. c. 265, § 15A ( b ) ; drug distribution, in violation of G. L. c. 94C, §§ 32 ( a ) and 32A ( a ) ; and other charges. He subsequently filed a motion for a new trial, seeking to withdraw his pleas. In connection with that motion, he filed several additional motions seeking postconviction discovery, appointment of counsel, judicial notice, and a writ of habeas corpus ad testificandum, all of which were denied. He then filed a petition in the county court for relief under G. L. c. 211, § 3, seeking review of the Superior Court judge's orders on the latter motions. A single justice of this court denied the petition without a hearing. Dew appeals. We affirm.

Our power of general superintendence under G. L. c. 211, § 3, is reserved for extraordinary circumstances, where a petitioner demonstrates both a substantial violation of a substantive right and the absence of an adequate alternative remedy. See Watson v. Walker , 447 Mass. 1014 , 1014, 854 N.E.2d 1247 (2006). Relief is properly denied where, as here, the petitioner has an adequate alternative avenue to seek review. See Tavares v. Commonwealth , 478 Mass. 1024 , 1024, 89 N.E.3d 1168 (2018). "An established route for the petitioner to obtain appellate review of the denial of his motion for postconviction discovery [and the other motions ancillary to his motion for a new trial] would be in connection with an appeal from the denial of his motion for a new trial." Donald v. Commonwealth , 437 Mass. 1007 , 1007, 770 N.E.2d 471 (2002). 1 The single justice therefore neither erred nor abused his discretion in denying the petition under G. L. c. 211, § 3.

Judgment affirmed .